diff --git a/spring-cloud-stream-binder-kafka/src/test/java/org/springframework/cloud/stream/binder/kafka/KafkaBinderTests.java b/spring-cloud-stream-binder-kafka/src/test/java/org/springframework/cloud/stream/binder/kafka/KafkaBinderTests.java
index a79d98441..6b3104a8c 100644
--- a/spring-cloud-stream-binder-kafka/src/test/java/org/springframework/cloud/stream/binder/kafka/KafkaBinderTests.java
+++ b/spring-cloud-stream-binder-kafka/src/test/java/org/springframework/cloud/stream/binder/kafka/KafkaBinderTests.java
@@ -323,10 +323,10 @@ public void testTrustedPackages() throws Exception {
 
 		moduleOutputChannel.send(message);
 		CountDownLatch latch = new CountDownLatch(1);
-		AtomicReference<Message<byte[]>> inboundMessageRef = new AtomicReference<>();
+		AtomicReference<Message<String>> inboundMessageRef = new AtomicReference<>();
 		moduleInputChannel.subscribe(message1 -> {
 			try {
-				inboundMessageRef.set((Message<byte[]>) message1);
+				inboundMessageRef.set((Message<String>) message1);
 			}
 			finally {
 				latch.countDown();
@@ -336,7 +336,7 @@ public void testTrustedPackages() throws Exception {
 
 
 		Assertions.assertThat(inboundMessageRef.get()).isNotNull();
-		Assertions.assertThat(new String(inboundMessageRef.get().getPayload(), StandardCharsets.UTF_8)).isEqualTo("foo");
+		Assertions.assertThat(inboundMessageRef.get().getPayload()).isEqualTo("foo");
 		Assertions.assertThat(inboundMessageRef.get().getHeaders().get(BinderHeaders.BINDER_ORIGINAL_CONTENT_TYPE)).isNull();
 		Assertions.assertThat(inboundMessageRef.get().getHeaders().get(MessageHeaders.CONTENT_TYPE))
 				.isEqualTo(MimeTypeUtils.TEXT_PLAIN);
@@ -374,10 +374,10 @@ public void testSendAndReceiveNoOriginalContentType() throws Exception {
 				.setHeader(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.TEXT_PLAIN).build();
 		moduleOutputChannel.send(message);
 		CountDownLatch latch = new CountDownLatch(1);
-		AtomicReference<Message<byte[]>> inboundMessageRef = new AtomicReference<>();
+		AtomicReference<Message<String>> inboundMessageRef = new AtomicReference<>();
 		moduleInputChannel.subscribe(message1 -> {
 			try {
-				inboundMessageRef.set((Message<byte[]>) message1);
+				inboundMessageRef.set((Message<String>) message1);
 			}
 			finally {
 				latch.countDown();
@@ -386,7 +386,7 @@ public void testSendAndReceiveNoOriginalContentType() throws Exception {
 		Assert.isTrue(latch.await(5, TimeUnit.SECONDS), "Failed to receive message");
 
 		assertThat(inboundMessageRef.get()).isNotNull();
-		assertThat(new String(inboundMessageRef.get().getPayload(), StandardCharsets.UTF_8)).isEqualTo("foo");
+		assertThat(inboundMessageRef.get().getPayload()).isEqualTo("foo");
 		assertThat(inboundMessageRef.get().getHeaders().get(MessageHeaders.CONTENT_TYPE))
 				.isEqualTo(MimeTypeUtils.TEXT_PLAIN);
 		producerBinding.unbind();
@@ -413,7 +413,7 @@ public void testSendAndReceive() throws Exception {
 				.setHeader(MessageHeaders.CONTENT_TYPE,
 						MimeTypeUtils.APPLICATION_OCTET_STREAM)
 				.build();
-		
+
 		// Let the consumer actually bind to the producer before sending a msg
 		binderBindUnbindLatency();
 		moduleOutputChannel.send(message);
@@ -433,13 +433,13 @@ public void testSendAndReceive() throws Exception {
 		assertThat(new String(inboundMessageRef.get().getPayload(), StandardCharsets.UTF_8)).isEqualTo("foo");
 		assertThat(inboundMessageRef.get().getHeaders().get(MessageHeaders.CONTENT_TYPE))
 				.isEqualTo(MimeTypeUtils.APPLICATION_OCTET_STREAM);
-		
+
 		Map<String, TopicInformation> topicsInUse = ((KafkaTestBinder)binder).getCoreBinder().getTopicsInUse();
 		assertThat(topicsInUse.keySet()).contains("foo.bar");
 		TopicInformation topic = topicsInUse.get("foo.bar");
 		assertThat(topic.isConsumerTopic()).isTrue();
 		assertThat(topic.getConsumerGroup()).isEqualTo("testSendAndReceive");
-		
+
 		producerBinding.unbind();
 		consumerBinding.unbind();
 	}
@@ -1471,7 +1471,7 @@ public void testAnonymousGroup() throws Exception {
 		TopicInformation topic = topicsInUse.get("defaultGroup.0");
 		assertThat(topic.isConsumerTopic()).isTrue();
 		assertThat(topic.getConsumerGroup()).startsWith("anonymous");
-		
+
 		producerBinding.unbind();
 		binding1.unbind();
 		binding2.unbind();
@@ -2392,10 +2392,10 @@ public void testBuiltinSerialization() throws Exception {
 			binderBindUnbindLatency();
 			moduleOutputChannel.send(message);
 			CountDownLatch latch = new CountDownLatch(1);
-			AtomicReference<Message<byte[]>> inboundMessageRef = new AtomicReference<>();
+			AtomicReference<Message<String>> inboundMessageRef = new AtomicReference<>();
 			moduleInputChannel.subscribe(message1 -> {
 				try {
-					inboundMessageRef.set((Message<byte[]>) message1);
+					inboundMessageRef.set((Message<String>) message1);
 				}
 				finally {
 					latch.countDown();
@@ -2404,7 +2404,7 @@ public void testBuiltinSerialization() throws Exception {
 			Assert.isTrue(latch.await(5, TimeUnit.SECONDS), "Failed to receive message");
 
 			assertThat(inboundMessageRef.get()).isNotNull();
-			assertThat(new String(inboundMessageRef.get().getPayload(), StandardCharsets.UTF_8)).isEqualTo("test");
+			assertThat(inboundMessageRef.get().getPayload()).isEqualTo("test");
 			assertThat(inboundMessageRef.get().getHeaders()).containsEntry("contentType", MimeTypeUtils.TEXT_PLAIN);
 		}
 		finally {