fix: Made the go testsuite skip PCAP related tests, if the library is…

… not installed.

fixes: #1567

plc4go/spi/transports/pcap/TransportInstance_test.go

@@ -106,6 +106,10 @@ func TestTransportInstance_Close(t *testing.T) {
 }
 
 func TestTransportInstance_Connect(t *testing.T) {
+	if !IsPcapAvailable() {
+		t.Skip("LibPCAP (unix/linux/mac) or NPcap (windows) is not installed, skipping test")
+	}
+
 	type fields struct {
 		DefaultBufferedTransportInstance transportUtils.DefaultBufferedTransportInstance
 		transportFile                    string
@@ -337,3 +341,13 @@ func TestTransportInstance_Write(t *testing.T) {
 		})
 	}
 }
+
+func IsPcapAvailable() (result bool) {
+	defer func() {
+		if err := recover(); err != nil {
+			result = false
+		}
+	}()
+	pcap.Version()
+	return true
+}