Add test

Signed-off-by: Pavol Loffay <ploffay@redhat.com>

exporter/kafkaexporter/jaeger_marshaller_test.go

@@ -45,8 +45,8 @@ func TestJaegerMarshaller(t *testing.T) {
 	require.NotNil(t, jaegerProtoBytes)
 
 	jsonMarshaller := &jsonpb.Marshaler{}
-	jsonBytes := new(bytes.Buffer)
-	jsonMarshaller.Marshal(jsonBytes, batches[0].Spans[0])
+	jsonByteBuffer := new(bytes.Buffer)
+	require.NoError(t, jsonMarshaller.Marshal(jsonByteBuffer, batches[0].Spans[0]))
 
 	tests := []struct {
 		unmarshaller Marshaller
@@ -67,7 +67,7 @@ func TestJaegerMarshaller(t *testing.T) {
 				},
 			},
 			encoding: "jaeger_json",
-			messages: []Message{{Value: jsonBytes.Bytes()}},
+			messages: []Message{{Value: jsonByteBuffer.Bytes()}},
 		},
 	}
 	for _, test := range tests {
@@ -79,3 +79,17 @@ func TestJaegerMarshaller(t *testing.T) {
 		})
 	}
 }
+
+func TestJaegerMarshaller_error_covert_traceID(t *testing.T) {
+	marshaller := jaegerMarshaller{
+		marshaller: jaegerProtoSpanMarshaller{},
+	}
+	td := pdata.NewTraces()
+	td.ResourceSpans().Resize(1)
+	td.ResourceSpans().At(0).InstrumentationLibrarySpans().Resize(1)
+	td.ResourceSpans().At(0).InstrumentationLibrarySpans().At(0).Spans().Resize(1)
+	// fails in zero traceID
+	messages, err := marshaller.Marshal(td)
+	require.Error(t, err)
+	assert.Nil(t, messages)
+}