sw test tool: Improve readability of padding data

    str(\"\\x00\" * (60 - 42))
->  str('\\x00' * (60 - 42))

    str(\"\\x11\" * (1500 - 54))
->  str('\\x11' * (1500 - 54))

    '\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'
->  str('\\x00' * 30)

Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

66 files changed, 390 insertions, 390 deletions

diff --git a/ryu/tests/switch/of13/action/00_OUTPUT.json b/ryu/tests/switch/of13/action/00_OUTPUT.json
index afcc1571..5759f17e 100644
--- a/ryu/tests/switch/of13/action/00_OUTPUT.json
+++ b/ryu/tests/switch/of13/action/00_OUTPUT.json
@@ -109,12 +109,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/15_SET_MPLS_TTL.json b/ryu/tests/switch/of13/action/15_SET_MPLS_TTL.json
index 5ee372a6..1d152a2c 100644
--- a/ryu/tests/switch/of13/action/15_SET_MPLS_TTL.json
+++ b/ryu/tests/switch/of13/action/15_SET_MPLS_TTL.json
@@ -164,13 +164,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=127)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/16_DEC_MPLS_TTL.json b/ryu/tests/switch/of13/action/16_DEC_MPLS_TTL.json
index c0f907a3..48f93245 100644
--- a/ryu/tests/switch/of13/action/16_DEC_MPLS_TTL.json
+++ b/ryu/tests/switch/of13/action/16_DEC_MPLS_TTL.json
@@ -158,13 +158,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=63)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/17_PUSH_VLAN.json b/ryu/tests/switch/of13/action/17_PUSH_VLAN.json
index a5694126..d498d3e4 100644
--- a/ryu/tests/switch/of13/action/17_PUSH_VLAN.json
+++ b/ryu/tests/switch/of13/action/17_PUSH_VLAN.json
@@ -161,13 +161,13 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/17_PUSH_VLAN_multiple.json b/ryu/tests/switch/of13/action/17_PUSH_VLAN_multiple.json
index ad7b5781..50b997e9 100644
--- a/ryu/tests/switch/of13/action/17_PUSH_VLAN_multiple.json
+++ b/ryu/tests/switch/of13/action/17_PUSH_VLAN_multiple.json
@@ -166,14 +166,14 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
                     "svlan(pcp=3, cfi=0, vid=100, ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/18_POP_VLAN.json b/ryu/tests/switch/of13/action/18_POP_VLAN.json
index c185dd83..4f68312b 100644
--- a/ryu/tests/switch/of13/action/18_POP_VLAN.json
+++ b/ryu/tests/switch/of13/action/18_POP_VLAN.json
@@ -177,12 +177,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/19_PUSH_MPLS.json b/ryu/tests/switch/of13/action/19_PUSH_MPLS.json
index 4f87a93f..6c0fe98a 100644
--- a/ryu/tests/switch/of13/action/19_PUSH_MPLS.json
+++ b/ryu/tests/switch/of13/action/19_PUSH_MPLS.json
@@ -161,13 +161,13 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(ttl=0)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/19_PUSH_MPLS_multiple.json b/ryu/tests/switch/of13/action/19_PUSH_MPLS_multiple.json
index 2694e9de..d60d300c 100644
--- a/ryu/tests/switch/of13/action/19_PUSH_MPLS_multiple.json
+++ b/ryu/tests/switch/of13/action/19_PUSH_MPLS_multiple.json
@@ -166,14 +166,14 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=0, label=100, exp=3, ttl=64)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/20_POP_MPLS.json b/ryu/tests/switch/of13/action/20_POP_MPLS.json
index 9d042cee..d9080618 100644
--- a/ryu/tests/switch/of13/action/20_POP_MPLS.json
+++ b/ryu/tests/switch/of13/action/20_POP_MPLS.json
@@ -162,12 +162,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/03_ETH_DST.json b/ryu/tests/switch/of13/action/25_SET_FIELD/03_ETH_DST.json
index ae1414e7..0a2fe33b 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/03_ETH_DST.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/03_ETH_DST.json
@@ -174,12 +174,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/04_ETH_SRC.json b/ryu/tests/switch/of13/action/25_SET_FIELD/04_ETH_SRC.json
index fcc57fa8..7416364a 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/04_ETH_SRC.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/04_ETH_SRC.json
@@ -174,12 +174,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/05_ETH_TYPE.json b/ryu/tests/switch/of13/action/25_SET_FIELD/05_ETH_TYPE.json
index 980a6bb3..0fd5bf3a 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/05_ETH_TYPE.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/05_ETH_TYPE.json
@@ -174,12 +174,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34888)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/06_VLAN_VID.json b/ryu/tests/switch/of13/action/25_SET_FIELD/06_VLAN_VID.json
index 72b02085..092003c3 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/06_VLAN_VID.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/06_VLAN_VID.json
@@ -179,13 +179,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/07_VLAN_PCP.json b/ryu/tests/switch/of13/action/25_SET_FIELD/07_VLAN_PCP.json
index d43ca781..92343700 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/07_VLAN_PCP.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/07_VLAN_PCP.json
@@ -197,13 +197,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/21_ARP_OP.json b/ryu/tests/switch/of13/action/25_SET_FIELD/21_ARP_OP.json
index 573b2609..75c237b8 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/21_ARP_OP.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/21_ARP_OP.json
@@ -56,12 +56,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=2, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -123,13 +123,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=2, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -227,12 +227,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=2, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -329,12 +329,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=2, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/22_ARP_SPA.json b/ryu/tests/switch/of13/action/25_SET_FIELD/22_ARP_SPA.json
index 89a6c9f8..991eb6c1 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/22_ARP_SPA.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/22_ARP_SPA.json
@@ -56,12 +56,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='10.10.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -123,13 +123,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='10.10.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -227,12 +227,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='10.10.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -329,12 +329,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='10.10.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/23_ARP_TPA.json b/ryu/tests/switch/of13/action/25_SET_FIELD/23_ARP_TPA.json
index 91f0dadf..f9f34485 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/23_ARP_TPA.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/23_ARP_TPA.json
@@ -56,12 +56,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -123,13 +123,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -227,12 +227,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -329,12 +329,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/24_ARP_SHA.json b/ryu/tests/switch/of13/action/25_SET_FIELD/24_ARP_SHA.json
index 056ad34d..4f845721 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/24_ARP_SHA.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/24_ARP_SHA.json
@@ -56,12 +56,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -123,13 +123,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -227,12 +227,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -329,12 +329,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/25_ARP_THA.json b/ryu/tests/switch/of13/action/25_SET_FIELD/25_ARP_THA.json
index d2cae428..88a879c6 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/25_ARP_THA.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/25_ARP_THA.json
@@ -56,12 +56,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -123,13 +123,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -227,12 +227,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -329,12 +329,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/34_MPLS_LABEL.json b/ryu/tests/switch/of13/action/25_SET_FIELD/34_MPLS_LABEL.json
index da1bc7ec..ac48e12c 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/34_MPLS_LABEL.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/34_MPLS_LABEL.json
@@ -197,13 +197,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/35_MPLS_TC.json b/ryu/tests/switch/of13/action/25_SET_FIELD/35_MPLS_TC.json
index 0d564ead..273c6aaa 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/35_MPLS_TC.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/35_MPLS_TC.json
@@ -197,13 +197,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=5, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/36_MPLS_BOS.json b/ryu/tests/switch/of13/action/25_SET_FIELD/36_MPLS_BOS.json
index 54abdb0e..0e498336 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/36_MPLS_BOS.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/36_MPLS_BOS.json
@@ -197,13 +197,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=0, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/37_PBB_ISID.json b/ryu/tests/switch/of13/action/25_SET_FIELD/37_PBB_ISID.json
index a9bf9c09..78e68301 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/37_PBB_ISID.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/37_PBB_ISID.json
@@ -217,7 +217,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
@@ -227,7 +227,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/25_SET_FIELD/38_TUNNEL_ID.json b/ryu/tests/switch/of13/action/25_SET_FIELD/38_TUNNEL_ID.json
index dbefaf13..893b32f0 100644
--- a/ryu/tests/switch/of13/action/25_SET_FIELD/38_TUNNEL_ID.json
+++ b/ryu/tests/switch/of13/action/25_SET_FIELD/38_TUNNEL_ID.json
@@ -267,12 +267,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/26_PUSH_PBB.json b/ryu/tests/switch/of13/action/26_PUSH_PBB.json
index 0dd4d396..f38894ad 100644
--- a/ryu/tests/switch/of13/action/26_PUSH_PBB.json
+++ b/ryu/tests/switch/of13/action/26_PUSH_PBB.json
@@ -163,14 +163,14 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=35047)",
                     "itag()",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/26_PUSH_PBB_multiple.json b/ryu/tests/switch/of13/action/26_PUSH_PBB_multiple.json
index 158f35f6..601a1be2 100644
--- a/ryu/tests/switch/of13/action/26_PUSH_PBB_multiple.json
+++ b/ryu/tests/switch/of13/action/26_PUSH_PBB_multiple.json
@@ -182,7 +182,7 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=35047)",
@@ -191,7 +191,7 @@
                     "itag()",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/action/27_POP_PBB.json b/ryu/tests/switch/of13/action/27_POP_PBB.json
index 665e29ed..4c440a10 100644
--- a/ryu/tests/switch/of13/action/27_POP_PBB.json
+++ b/ryu/tests/switch/of13/action/27_POP_PBB.json
@@ -169,14 +169,14 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
diff --git a/ryu/tests/switch/of13/match/00_IN_PORT.json b/ryu/tests/switch/of13/match/00_IN_PORT.json
index 4d88eebc..8a45adb5 100644
--- a/ryu/tests/switch/of13/match/00_IN_PORT.json
+++ b/ryu/tests/switch/of13/match/00_IN_PORT.json
@@ -348,12 +348,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -399,12 +399,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -449,7 +449,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/02_METADATA.json b/ryu/tests/switch/of13/match/02_METADATA.json
index 65e00d65..41664639 100644
--- a/ryu/tests/switch/of13/match/02_METADATA.json
+++ b/ryu/tests/switch/of13/match/02_METADATA.json
@@ -509,12 +509,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -583,12 +583,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -656,7 +656,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/02_METADATA_Mask.json b/ryu/tests/switch/of13/match/02_METADATA_Mask.json
index 59b63aef..c6c5570e 100644
--- a/ryu/tests/switch/of13/match/02_METADATA_Mask.json
+++ b/ryu/tests/switch/of13/match/02_METADATA_Mask.json
@@ -516,12 +516,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -591,12 +591,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -665,7 +665,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/03_ETH_DST.json b/ryu/tests/switch/of13/match/03_ETH_DST.json
index 52db0c96..c32bf41a 100644
--- a/ryu/tests/switch/of13/match/03_ETH_DST.json
+++ b/ryu/tests/switch/of13/match/03_ETH_DST.json
@@ -348,12 +348,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -399,12 +399,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -449,7 +449,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/03_ETH_DST_Mask.json b/ryu/tests/switch/of13/match/03_ETH_DST_Mask.json
index 8376c16b..d795ee7a 100644
--- a/ryu/tests/switch/of13/match/03_ETH_DST_Mask.json
+++ b/ryu/tests/switch/of13/match/03_ETH_DST_Mask.json
@@ -355,12 +355,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -407,12 +407,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -458,7 +458,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/04_ETH_SRC.json b/ryu/tests/switch/of13/match/04_ETH_SRC.json
index 29fb2c93..7029f589 100644
--- a/ryu/tests/switch/of13/match/04_ETH_SRC.json
+++ b/ryu/tests/switch/of13/match/04_ETH_SRC.json
@@ -348,12 +348,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -399,12 +399,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -449,7 +449,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/04_ETH_SRC_Mask.json b/ryu/tests/switch/of13/match/04_ETH_SRC_Mask.json
index 4f4f94b5..2c4e8e53 100644
--- a/ryu/tests/switch/of13/match/04_ETH_SRC_Mask.json
+++ b/ryu/tests/switch/of13/match/04_ETH_SRC_Mask.json
@@ -355,12 +355,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -407,12 +407,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -458,7 +458,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/05_ETH_TYPE.json b/ryu/tests/switch/of13/match/05_ETH_TYPE.json
index 8adbd702..8b4249a9 100644
--- a/ryu/tests/switch/of13/match/05_ETH_TYPE.json
+++ b/ryu/tests/switch/of13/match/05_ETH_TYPE.json
@@ -348,12 +348,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -399,12 +399,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -449,7 +449,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/06_VLAN_VID.json b/ryu/tests/switch/of13/match/06_VLAN_VID.json
index 44daf01c..1181768a 100644
--- a/ryu/tests/switch/of13/match/06_VLAN_VID.json
+++ b/ryu/tests/switch/of13/match/06_VLAN_VID.json
@@ -359,13 +359,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -412,13 +412,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -464,7 +464,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/06_VLAN_VID_Mask.json b/ryu/tests/switch/of13/match/06_VLAN_VID_Mask.json
index e1a5b0b3..6df10c7e 100644
--- a/ryu/tests/switch/of13/match/06_VLAN_VID_Mask.json
+++ b/ryu/tests/switch/of13/match/06_VLAN_VID_Mask.json
@@ -366,13 +366,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -420,13 +420,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -473,7 +473,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/07_VLAN_PCP.json b/ryu/tests/switch/of13/match/07_VLAN_PCP.json
index 2c2ea24a..498ce890 100644
--- a/ryu/tests/switch/of13/match/07_VLAN_PCP.json
+++ b/ryu/tests/switch/of13/match/07_VLAN_PCP.json
@@ -408,13 +408,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -468,13 +468,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -527,7 +527,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/21_ARP_OP.json b/ryu/tests/switch/of13/match/21_ARP_OP.json
index 3e47a59e..c153fa5e 100644
--- a/ryu/tests/switch/of13/match/21_ARP_OP.json
+++ b/ryu/tests/switch/of13/match/21_ARP_OP.json
@@ -46,12 +46,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -103,12 +103,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -159,7 +159,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -214,13 +214,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -273,13 +273,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -331,7 +331,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -422,12 +422,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -516,12 +516,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -609,7 +609,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -699,12 +699,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -792,12 +792,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -884,7 +884,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/22_ARP_SPA.json b/ryu/tests/switch/of13/match/22_ARP_SPA.json
index 299df340..daf251db 100644
--- a/ryu/tests/switch/of13/match/22_ARP_SPA.json
+++ b/ryu/tests/switch/of13/match/22_ARP_SPA.json
@@ -46,12 +46,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -103,12 +103,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -159,7 +159,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -214,13 +214,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -273,13 +273,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -331,7 +331,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -422,12 +422,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -516,12 +516,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -609,7 +609,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -699,12 +699,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -792,12 +792,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -884,7 +884,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/22_ARP_SPA_Mask.json b/ryu/tests/switch/of13/match/22_ARP_SPA_Mask.json
index 60da63c9..7df99cbb 100644
--- a/ryu/tests/switch/of13/match/22_ARP_SPA_Mask.json
+++ b/ryu/tests/switch/of13/match/22_ARP_SPA_Mask.json
@@ -47,12 +47,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -105,12 +105,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -162,7 +162,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -218,13 +218,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -278,13 +278,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -337,7 +337,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -429,12 +429,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -524,12 +524,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -618,7 +618,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -709,12 +709,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -803,12 +803,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -896,7 +896,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/23_ARP_TPA.json b/ryu/tests/switch/of13/match/23_ARP_TPA.json
index def206e3..97a597c0 100644
--- a/ryu/tests/switch/of13/match/23_ARP_TPA.json
+++ b/ryu/tests/switch/of13/match/23_ARP_TPA.json
@@ -46,12 +46,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -103,12 +103,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -159,7 +159,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -214,13 +214,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -273,13 +273,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -331,7 +331,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -422,12 +422,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -516,12 +516,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -609,7 +609,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -699,12 +699,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -792,12 +792,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -884,7 +884,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/23_ARP_TPA_Mask.json b/ryu/tests/switch/of13/match/23_ARP_TPA_Mask.json
index 69052e3f..12a55382 100644
--- a/ryu/tests/switch/of13/match/23_ARP_TPA_Mask.json
+++ b/ryu/tests/switch/of13/match/23_ARP_TPA_Mask.json
@@ -47,12 +47,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -105,12 +105,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -162,7 +162,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -218,13 +218,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -278,13 +278,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -337,7 +337,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -429,12 +429,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -524,12 +524,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -618,7 +618,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -709,12 +709,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -803,12 +803,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -896,7 +896,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/24_ARP_SHA.json b/ryu/tests/switch/of13/match/24_ARP_SHA.json
index b6ceaf16..e79aaea6 100644
--- a/ryu/tests/switch/of13/match/24_ARP_SHA.json
+++ b/ryu/tests/switch/of13/match/24_ARP_SHA.json
@@ -46,12 +46,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -103,12 +103,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -159,7 +159,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -214,13 +214,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -273,13 +273,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -331,7 +331,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -422,12 +422,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -516,12 +516,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -609,7 +609,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -699,12 +699,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -792,12 +792,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -884,7 +884,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/24_ARP_SHA_Mask.json b/ryu/tests/switch/of13/match/24_ARP_SHA_Mask.json
index 1a0c7338..93e44746 100644
--- a/ryu/tests/switch/of13/match/24_ARP_SHA_Mask.json
+++ b/ryu/tests/switch/of13/match/24_ARP_SHA_Mask.json
@@ -47,12 +47,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -105,12 +105,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -162,7 +162,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -218,13 +218,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -278,13 +278,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -337,7 +337,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -429,12 +429,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -524,12 +524,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -618,7 +618,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -709,12 +709,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -803,12 +803,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -896,7 +896,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/25_ARP_THA.json b/ryu/tests/switch/of13/match/25_ARP_THA.json
index 2fc1dfca..559d1bf5 100644
--- a/ryu/tests/switch/of13/match/25_ARP_THA.json
+++ b/ryu/tests/switch/of13/match/25_ARP_THA.json
@@ -46,12 +46,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -103,12 +103,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -159,7 +159,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -214,13 +214,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -273,13 +273,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -331,7 +331,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -422,12 +422,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -516,12 +516,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -609,7 +609,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -699,12 +699,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -792,12 +792,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -884,7 +884,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/25_ARP_THA_Mask.json b/ryu/tests/switch/of13/match/25_ARP_THA_Mask.json
index c600c781..38bde5f1 100644
--- a/ryu/tests/switch/of13/match/25_ARP_THA_Mask.json
+++ b/ryu/tests/switch/of13/match/25_ARP_THA_Mask.json
@@ -47,12 +47,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -105,12 +105,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -162,7 +162,7 @@
                 "ingress":[
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     0
@@ -218,13 +218,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -278,13 +278,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=33024)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -337,7 +337,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=33024)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
@@ -429,12 +429,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -524,12 +524,12 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -618,7 +618,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
@@ -709,12 +709,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -803,12 +803,12 @@
                     "itag(sid=100)",
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -896,7 +896,7 @@
                     "itag(sid=203)",
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/34_MPLS_LABEL.json b/ryu/tests/switch/of13/match/34_MPLS_LABEL.json
index 34bc8356..05628c55 100644
--- a/ryu/tests/switch/of13/match/34_MPLS_LABEL.json
+++ b/ryu/tests/switch/of13/match/34_MPLS_LABEL.json
@@ -401,13 +401,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -460,13 +460,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -518,7 +518,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/35_MPLS_TC.json b/ryu/tests/switch/of13/match/35_MPLS_TC.json
index df239c9b..e8038d70 100644
--- a/ryu/tests/switch/of13/match/35_MPLS_TC.json
+++ b/ryu/tests/switch/of13/match/35_MPLS_TC.json
@@ -401,13 +401,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -460,13 +460,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -518,7 +518,7 @@
                     "ethernet(dst='ba:bb:bb:bb:bb:bb', src='aa:aa:aa:aa:aa:aa', ethertype=34887)",
                     "mpls(bsb=1, label=203, exp=5, ttl=127)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/36_MPLS_BOS.json b/ryu/tests/switch/of13/match/36_MPLS_BOS.json
index 997e7be6..6cc47aa8 100644
--- a/ryu/tests/switch/of13/match/36_MPLS_BOS.json
+++ b/ryu/tests/switch/of13/match/36_MPLS_BOS.json
@@ -403,13 +403,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -462,13 +462,13 @@
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34887)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -521,7 +521,7 @@
                     "mpls(bsb=0, label=203, exp=5, ttl=127)",
                     "mpls(bsb=1, label=100, exp=3, ttl=64)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/37_PBB_ISID.json b/ryu/tests/switch/of13/match/37_PBB_ISID.json
index 015c8e3e..fb9b7857 100644
--- a/ryu/tests/switch/of13/match/37_PBB_ISID.json
+++ b/ryu/tests/switch/of13/match/37_PBB_ISID.json
@@ -445,7 +445,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
@@ -455,7 +455,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -512,7 +512,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
@@ -522,7 +522,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -578,7 +578,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/37_PBB_ISID_Mask.json b/ryu/tests/switch/of13/match/37_PBB_ISID_Mask.json
index a855f5a9..644ffc16 100644
--- a/ryu/tests/switch/of13/match/37_PBB_ISID_Mask.json
+++ b/ryu/tests/switch/of13/match/37_PBB_ISID_Mask.json
@@ -452,7 +452,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
@@ -462,7 +462,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -520,7 +520,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34984)",
@@ -530,7 +530,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=3, cfi=0, vid=100, ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ]
             }
         ]
@@ -587,7 +587,7 @@
                     "svlan(ethertype=33024, vid=10)",
                     "vlan(pcp=5, cfi=0, vid=203, ethertype=2054)",
                     "arp(dst_ip='10.10.20.20',dst_mac='ba:bb:bb:bb:bb:bb', opcode=2, src_ip='10.10.10.10',src_mac='aa:aa:aa:aa:aa:aa')",
-                    "'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"
+                    "str('\\x00' * 30)"
                 ],
                 "table-miss":[
                     0
diff --git a/ryu/tests/switch/of13/match/38_TUNNEL_ID.json b/ryu/tests/switch/of13/match/38_TUNNEL_ID.json
index 86d3f623..4b739c58 100644
--- a/ryu/tests/switch/of13/match/38_TUNNEL_ID.json
+++ b/ryu/tests/switch/of13/match/38_TUNNEL_ID.json
@@ -635,12 +635,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -727,12 +727,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -818,7 +818,7 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/match/38_TUNNEL_ID_Mask.json b/ryu/tests/switch/of13/match/38_TUNNEL_ID_Mask.json
index b7e91c6c..99aa0418 100644
--- a/ryu/tests/switch/of13/match/38_TUNNEL_ID_Mask.json
+++ b/ryu/tests/switch/of13/match/38_TUNNEL_ID_Mask.json
@@ -642,12 +642,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "egress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -735,12 +735,12 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "PACKET_IN":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ]
             }
         ]
@@ -827,7 +827,7 @@
                 "ingress":[
                     "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                     "arp(dst_ip='192.168.20.20',dst_mac='22:22:22:22:22:22', opcode=1, src_ip='192.168.10.10',src_mac='12:11:11:11:11:11')",
-                    "str(\"\\x00\" * (60 - 42))"
+                    "str('\\x00' * (60 - 42))"
                 ],
                 "table-miss":[
                     1
diff --git a/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_00_1M.json b/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_00_1M.json
index 004beb95..bcfb44fa 100644
--- a/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_00_1M.json
+++ b/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_00_1M.json
@@ -59,7 +59,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":175,
                         "duration_time":30
@@ -144,7 +144,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":175,
                         "duration_time":30
@@ -228,7 +228,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":175,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_01_10M.json b/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_01_10M.json
index e6239023..5385ba13 100644
--- a/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_01_10M.json
+++ b/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_01_10M.json
@@ -59,7 +59,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":1750,
                         "duration_time":30
@@ -144,7 +144,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":1750,
                         "duration_time":30
@@ -228,7 +228,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":1750,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_02_100M.json b/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_02_100M.json
index 718027f5..4c1b551d 100644
--- a/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_02_100M.json
+++ b/ryu/tests/switch/of13/meter/01_DROP_00_KBPS_02_100M.json
@@ -59,7 +59,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":17500,
                         "duration_time":30
@@ -144,7 +144,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":17500,
                         "duration_time":30
@@ -228,7 +228,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":17500,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_00_100.json b/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_00_100.json
index 9947d0bc..1ab9d086 100644
--- a/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_00_100.json
+++ b/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_00_100.json
@@ -60,7 +60,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":200,
                         "duration_time":30
@@ -146,7 +146,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":200,
                         "duration_time":30
@@ -231,7 +231,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":200,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_01_1000.json b/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_01_1000.json
index 4eabee07..d67d89fd 100644
--- a/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_01_1000.json
+++ b/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_01_1000.json
@@ -60,7 +60,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":2000,
                         "duration_time":30
@@ -146,7 +146,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":2000,
                         "duration_time":30
@@ -231,7 +231,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":2000,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_02_10000.json b/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_02_10000.json
index 70a2cc1f..a2dfc47c 100644
--- a/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_02_10000.json
+++ b/ryu/tests/switch/of13/meter/01_DROP_01_PKTPS_02_10000.json
@@ -60,7 +60,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":20000,
                         "duration_time":30
@@ -146,7 +146,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":20000,
                         "duration_time":30
@@ -231,7 +231,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":20000,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_00_1M.json b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_00_1M.json
index 6e0a417a..c3e5fe21 100644
--- a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_00_1M.json
+++ b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_00_1M.json
@@ -60,7 +60,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6, tos=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":175,
                         "duration_time":30
@@ -183,7 +183,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6, traffic_class=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":175,
                         "duration_time":30
@@ -305,7 +305,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":175,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_01_10M.json b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_01_10M.json
index 8516e8fc..5bf32c02 100644
--- a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_01_10M.json
+++ b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_01_10M.json
@@ -60,7 +60,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6, tos=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":1750,
                         "duration_time":30
@@ -183,7 +183,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6, traffic_class=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":1750,
                         "duration_time":30
@@ -305,7 +305,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":1750,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_02_100M.json b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_02_100M.json
index 77656d90..67326205 100644
--- a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_02_100M.json
+++ b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_00_KBPS_02_100M.json
@@ -60,7 +60,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6, tos=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":17500,
                         "duration_time":30
@@ -183,7 +183,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6, traffic_class=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":17500,
                         "duration_time":30
@@ -305,7 +305,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":17500,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_00_100.json b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_00_100.json
index bc54f3bc..131c73f2 100644
--- a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_00_100.json
+++ b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_00_100.json
@@ -61,7 +61,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6, tos=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":200,
                         "duration_time":30
@@ -185,7 +185,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6, traffic_class=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":200,
                         "duration_time":30
@@ -308,7 +308,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":200,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_01_1000.json b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_01_1000.json
index 07e4b461..b3008eaf 100644
--- a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_01_1000.json
+++ b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_01_1000.json
@@ -61,7 +61,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6, tos=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":2000,
                         "duration_time":30
@@ -185,7 +185,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6, traffic_class=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":2000,
                         "duration_time":30
@@ -308,7 +308,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":2000,
                         "duration_time":30
diff --git a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_02_10000.json b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_02_10000.json
index 0f1eb6b8..ff4dee40 100644
--- a/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_02_10000.json
+++ b/ryu/tests/switch/of13/meter/02_DSCP_REMARK_01_PKTPS_02_10000.json
@@ -61,7 +61,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2048)",
                             "ipv4(proto=6, tos=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 54))"
+                            "str('\\x11' * (1500 - 54))"
                         ],
                         "pktps":20000,
                         "duration_time":30
@@ -185,7 +185,7 @@
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=34525)",
                             "ipv6(nxt=6, traffic_class=96)",
                             "tcp()",
-                            "str(\"\\x11\" * (1500 - 74))"
+                            "str('\\x11' * (1500 - 74))"
                         ],
                         "pktps":20000,
                         "duration_time":30
@@ -308,7 +308,7 @@
                         "data":[
                             "ethernet(dst='22:22:22:22:22:22', src='12:11:11:11:11:11', ethertype=2054)",
                             "arp(dst_mac='22:22:22:22:22:22', src_mac='12:11:11:11:11:11')",
-                            "str(\"\\x11\" * (1500 - 42))"
+                            "str('\\x11' * (1500 - 42))"
                         ],
                         "pktps":20000,
                         "duration_time":30