DomainSearchList: tests for FromBytes, ToBytes, and Getter

Signed-off-by: Chris Koch <chrisko@google.com>

2 files changed, 75 insertions, 36 deletions

diff --git a/dhcpv6/option_domainsearchlist_test.go b/dhcpv6/option_domainsearchlist_test.go
index c03759c..3881523 100644
--- a/dhcpv6/option_domainsearchlist_test.go
+++ b/dhcpv6/option_domainsearchlist_test.go
@@ -1,49 +1,84 @@
 package dhcpv6
 
 import (
+	"errors"
+	"fmt"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/insomniacslk/dhcp/rfc1035label"
 	"github.com/stretchr/testify/require"
+	"github.com/u-root/uio/uio"
 )
 
-func TestParseOptDomainSearchList(t *testing.T) {
-	data := []byte{
-		7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
-		6, 's', 'u', 'b', 'n', 'e', 't', 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'o', 'r', 'g', 0,
-	}
-	var opt optDomainSearchList
-	err := opt.FromBytes(data)
-	require.NoError(t, err)
-	require.Equal(t, OptionDomainSearchList, opt.Code())
-	require.Equal(t, 2, len(opt.DomainSearchList.Labels))
-	require.Equal(t, "example.com", opt.DomainSearchList.Labels[0])
-	require.Equal(t, "subnet.example.org", opt.DomainSearchList.Labels[1])
-	require.Contains(t, opt.String(), "example.com subnet.example.org", "String() should contain the correct domain search output")
-}
-
-func TestOptDomainSearchListToBytes(t *testing.T) {
-	expected := []byte{
-		7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
-		6, 's', 'u', 'b', 'n', 'e', 't', 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'o', 'r', 'g', 0,
-	}
-	opt := OptDomainSearchList(
-		&rfc1035label.Labels{
-			Labels: []string{
-				"example.com",
-				"subnet.example.org",
+func TestDomainSearchListParseAndGetter(t *testing.T) {
+	for i, tt := range []struct {
+		buf  []byte
+		err  error
+		want *rfc1035label.Labels
+	}{
+		{
+			buf: []byte{
+				0, 24, // Domain Search List option
+				0, 33, // length
+				7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
+				6, 's', 'u', 'b', 'n', 'e', 't', 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'o', 'r', 'g', 0,
+			},
+			want: &rfc1035label.Labels{
+				Labels: []string{
+					"example.com",
+					"subnet.example.org",
+				},
 			},
 		},
-	)
-	require.Equal(t, expected, opt.ToBytes())
-}
+		{
+			buf: []byte{
+				0, 24, // Domain Search List option
+				0, 22, // length
+				7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
+				6, 's', 'u', 'b', 'n', 'e', 't', 7, 'e', // truncated
+			},
+			err: rfc1035label.ErrBufferTooShort,
+		},
+		{
+			buf:  nil,
+			want: nil,
+		},
+		{
+			buf:  []byte{0, 24, 0},
+			want: nil,
+			err:  uio.ErrUnreadBytes,
+		},
+	} {
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+			var mo MessageOptions
+			if err := mo.FromBytes(tt.buf); !errors.Is(err, tt.err) {
+				t.Errorf("FromBytes = %v, want %v", err, tt.err)
+			}
+			got := mo.DomainSearchList()
+			if !cmp.Equal(got, tt.want, cmpopts.IgnoreUnexported(rfc1035label.Labels{})) {
+				t.Errorf("DomainSearchList = %v, want %v", got, tt.want)
+			}
 
-func TestParseOptDomainSearchListInvalidLength(t *testing.T) {
-	data := []byte{
-		7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
-		6, 's', 'u', 'b', 'n', 'e', 't', 7, 'e', // truncated
+			if tt.want != nil {
+				var m MessageOptions
+				m.Add(OptDomainSearchList(tt.want))
+				got := m.ToBytes()
+				if diff := cmp.Diff(tt.buf, got); diff != "" {
+					t.Errorf("ToBytes mismatch (-want, +got): %s", diff)
+				}
+			}
+		})
 	}
-	var opt optDomainSearchList
-	err := opt.FromBytes(data)
-	require.Error(t, err, "A truncated OptDomainSearchList should return an error")
+}
+
+func TestOptDomainSearchListString(t *testing.T) {
+	opt := OptDomainSearchList(&rfc1035label.Labels{
+		Labels: []string{
+			"example.com",
+			"subnet.example.org",
+		},
+	})
+	require.Contains(t, opt.String(), "example.com subnet.example.org", "String() should contain the correct domain search output")
 }
diff --git a/rfc1035label/label.go b/rfc1035label/label.go
index 042c17b..f727ec6 100644
--- a/rfc1035label/label.go
+++ b/rfc1035label/label.go
@@ -89,6 +89,10 @@ func FromBytes(data []byte) (*Labels, error) {
 	return &l, nil
 }
 
+// ErrBufferTooShort is returned when the label cannot be parsed due to a wrong
+// length or missing bytes.
+var ErrBufferTooShort = errors.New("rfc1035label: buffer too short")
+
 // fromBytes decodes a serialized stream and returns a list of labels
 func labelsFromBytes(buf []byte) ([]string, error) {
 	var (
@@ -132,7 +136,7 @@ func labelsFromBytes(buf []byte) ([]string, error) {
 			pos = off
 		} else {
 			if pos+length > len(buf) {
-				return nil, errors.New("rfc1035label: buffer too short")
+				return nil, ErrBufferTooShort
 			}
 			chunk = string(buf[pos : pos+length])
 			if label != "" {