Check for errors in test code

Recent versions of errcheck have started checking in _test.go files as well,
revealing a handful more errors that need handling.

broker_test.go

@@ -11,17 +11,17 @@ func ExampleBroker() error {
 	if err != nil {
 		return err
 	}
-	defer broker.Close()
 
 	request := MetadataRequest{Topics: []string{"myTopic"}}
 	response, err := broker.GetMetadata("myClient", &request)
 	if err != nil {
+		_ = broker.Close()
 		return err
 	}
 
 	fmt.Println("There are", len(response.Topics), "topics active in the cluster.")
 
-	return nil
+	return broker.Close()
 }
 
 type mockEncoder struct {
@@ -29,8 +29,7 @@ type mockEncoder struct {
 }
 
 func (m mockEncoder) encode(pe packetEncoder) error {
-	pe.putRawBytes(m.bytes)
-	return nil
+	return pe.putRawBytes(m.bytes)
 }
 
 func TestBrokerAccessors(t *testing.T) {

consumer_test.go

@@ -301,7 +301,11 @@ func ExampleConsumerWithSelect() {
 	} else {
 		fmt.Println("> connected")
 	}
-	defer client.Close()
+	defer func() {
+		if err := client.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	master, err := NewConsumer(client, nil)
 	if err != nil {
@@ -316,7 +320,11 @@ func ExampleConsumerWithSelect() {
 	} else {
 		fmt.Println("> consumer ready")
 	}
-	defer consumer.Close()
+	defer func() {
+		if err := consumer.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	msgCount := 0
 
@@ -342,7 +350,11 @@ func ExampleConsumerWithGoroutines() {
 	} else {
 		fmt.Println("> connected")
 	}
-	defer client.Close()
+	defer func() {
+		if err := client.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	master, err := NewConsumer(client, nil)
 	if err != nil {
@@ -357,7 +369,11 @@ func ExampleConsumerWithGoroutines() {
 	} else {
 		fmt.Println("> consumer ready")
 	}
-	defer consumer.Close()
+	defer func() {
+		if err := consumer.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	var (
 		wg       sync.WaitGroup

functional_test.go

@@ -24,10 +24,10 @@ func init() {
 		kafkaAddr = "localhost:6667"
 	}
 
-	c, err := net.Dial("tcp", kafkaAddr)
-	if err == nil {
-		kafkaIsAvailable = true
-		c.Close()
+	if c, err := net.Dial("tcp", kafkaAddr); err == nil {
+		if err = c.Close(); err == nil {
+			kafkaIsAvailable = true
+		}
 	}
 
 	kafkaShouldBeAvailable = os.Getenv("CI") != ""

partitioner_test.go

@@ -92,7 +92,9 @@ func TestHashPartitioner(t *testing.T) {
 
 	buf := make([]byte, 256)
 	for i := 1; i < 50; i++ {
-		rand.Read(buf)
+		if _, err := rand.Read(buf); err != nil {
+			t.Error(err)
+		}
 		assertPartitioningConsistent(t, partitioner, ByteEncoder(buf), 50)
 	}
 }

producer_test.go

@@ -575,13 +575,21 @@ func ExampleProducer() {
 	} else {
 		fmt.Println("> connected")
 	}
-	defer client.Close()
+	defer func() {
+		if err := client.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	producer, err := NewProducer(client, nil)
 	if err != nil {
 		panic(err)
 	}
-	defer producer.Close()
+	defer func() {
+		if err := producer.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	for {
 		select {
@@ -600,13 +608,21 @@ func ExampleSyncProducer() {
 	} else {
 		fmt.Println("> connected")
 	}
-	defer client.Close()
+	defer func() {
+		if err := client.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	producer, err := NewSyncProducer(client, nil)
 	if err != nil {
 		panic(err)
 	}
-	defer producer.Close()
+	defer func() {
+		if err := producer.Close(); err != nil {
+			panic(err)
+		}
+	}()
 
 	for {
 		partition, offset, err := producer.SendMessage("my_topic", nil, StringEncoder("testing 123"))