2 files changed, 12 insertions, 7 deletions
diff --git a/test/packetimpact/testbench/connections.go b/test/packetimpact/testbench/connections.go
index 50b9ccf68..576577310 100644
--- a/test/packetimpact/testbench/connections.go
+++ b/test/packetimpact/testbench/connections.go
@@ -306,11 +306,11 @@ func (s *tcpState) incoming(received Layer) Layer {
 	if s.remoteSeqNum != nil {
 		newIn.SeqNum = Uint32(uint32(*s.remoteSeqNum))
 	}
-	if s.localSeqNum != nil && (*tcpReceived.Flags&header.TCPFlagAck) != 0 {
+	if seq, flags := s.localSeqNum, tcpReceived.Flags; seq != nil && flags != nil && *flags&header.TCPFlagAck != 0 {
 		// The caller didn't specify an AckNum so we'll expect the calculated one,
 		// but only if the ACK flag is set because the AckNum is not valid in a
 		// header if ACK is not set.
-		newIn.AckNum = Uint32(uint32(*s.localSeqNum))
+		newIn.AckNum = Uint32(uint32(*seq))
 	}
 	return &newIn
 }
@@ -603,9 +603,9 @@ func (conn *Connection) ExpectFrame(t *testing.T, layers Layers, timeout time.Du
 		}
 		if gotLayers == nil {
 			if errs == nil {
-				return nil, fmt.Errorf("got no frames matching %v during %s", layers, timeout)
+				return nil, fmt.Errorf("got no frames matching %s during %s", layers, timeout)
 			}
-			return nil, fmt.Errorf("got frames %w want %v during %s", errs, layers, timeout)
+			return nil, fmt.Errorf("got frames:\n%w want %s during %s", errs, layers, timeout)
 		}
 		if conn.match(layers, gotLayers) {
 			for i, s := range conn.layerStates {
@@ -615,7 +615,12 @@ func (conn *Connection) ExpectFrame(t *testing.T, layers Layers, timeout time.Du
 			}
 			return gotLayers, nil
 		}
-		errs = multierr.Combine(errs, &layersError{got: gotLayers, want: conn.incoming(gotLayers)})
+		want := conn.incoming(layers)
+		if err := want.merge(layers); err != nil {
+			errs = multierr.Combine(errs, err)
+		} else {
+			errs = multierr.Combine(errs, &layersError{got: gotLayers, want: want})
+		}
 	}
 }
 
diff --git a/test/packetimpact/testbench/layers.go b/test/packetimpact/testbench/layers.go
index dcff4ab36..19e6b8d7d 100644
--- a/test/packetimpact/testbench/layers.go
+++ b/test/packetimpact/testbench/layers.go
@@ -505,13 +505,13 @@ func (l *IPv6) ToBytes() ([]byte, error) {
 		}
 	}
 	if l.NextHeader != nil {
-		fields.NextHeader = *l.NextHeader
+		fields.TransportProtocol = tcpip.TransportProtocolNumber(*l.NextHeader)
 	} else {
 		nh, err := nextHeaderByLayer(l.next())
 		if err != nil {
 			return nil, err
 		}
-		fields.NextHeader = nh
+		fields.TransportProtocol = tcpip.TransportProtocolNumber(nh)
 	}
 	if l.HopLimit != nil {
 		fields.HopLimit = *l.HopLimit