Integrate metadata test with default test

(the main differences between the various test functions are the organization of
brokers and flushes and error patterns, we don't really need separate tests if
all of that stays the same)

producer_test.go

@@ -128,7 +128,7 @@ func TestProducer(t *testing.T) {
 	defer safeClose(t, producer)
 
 	for i := 0; i < 10; i++ {
-		producer.Input() <- &MessageToSend{Topic: "my_topic", Key: nil, Value: StringEncoder(TestMessage)}
+		producer.Input() <- &MessageToSend{Topic: "my_topic", Key: nil, Value: StringEncoder(TestMessage), Metadata: i}
 	}
 	for i := 0; i < 10; i++ {
 		select {
@@ -141,6 +141,9 @@ func TestProducer(t *testing.T) {
 			if msg.flags != 0 {
 				t.Error("Message had flags set")
 			}
+			if msg.Metadata.(int) != i {
+				t.Error("Message metadata did not match")
+			}
 		}
 	}
 }
@@ -331,73 +334,6 @@ func TestProducerFailureRetry(t *testing.T) {
 	safeClose(t, client)
 }
 
-func TestMessageMetadata(t *testing.T) {
-	broker1 := NewMockBroker(t, 1)
-	broker2 := NewMockBroker(t, 2)
-	defer broker1.Close()
-	defer broker2.Close()
-
-	response1 := new(MetadataResponse)
-	response1.AddBroker(broker2.Addr(), broker2.BrokerID())
-	response1.AddTopicPartition("my_topic", 0, broker2.BrokerID(), nil, nil, NoError)
-	broker1.Returns(response1)
-
-	response2 := new(ProduceResponse)
-	response2.AddTopicPartition("my_topic", 0, NoError)
-	broker2.Returns(response2)
-
-	client, err := NewClient("client_id", []string{broker1.Addr()}, nil)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer safeClose(t, client)
-
-	config := NewProducerConfig()
-	config.FlushMsgCount = 10
-	config.AckSuccesses = true
-	producer, err := NewProducer(client, config)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer safeClose(t, producer)
-
-	type testMetadata struct {
-		id        int64
-		startTime uint64
-		origin    string
-	}
-
-	for i := 0; i < 10; i++ {
-		metadata := &testMetadata{
-			int64(i),
-			uint64(1234567890),
-			"tcp://127.0.0.1:8555",
-		}
-		producer.Input() <- &MessageToSend{Topic: "my_topic", Key: nil, Value: StringEncoder(TestMessage), Metadata: metadata}
-	}
-	for i := 0; i < 10; i++ {
-		select {
-		case msg := <-producer.Errors():
-			t.Error(msg.Err)
-			if msg.Msg.flags != 0 {
-				t.Error("Message had flags set")
-			}
-		case msg := <-producer.Successes():
-			if msg.flags != 0 {
-				t.Error("Message had flags set")
-			}
-			md, ok := msg.Metadata.(*testMetadata)
-			if !ok {
-				t.Error("Metadata not retrieved in success message")
-			}
-			if md.id != int64(i) {
-				t.Errorf("Metadata id in response %d does not match metadata input %d", md.id, i)
-			}
-
-		}
-	}
-}
-
 func ExampleProducer() {
 	client, err := NewClient("client_id", []string{"localhost:9092"}, NewClientConfig())
 	if err != nil {