diff --git a/spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/WebTestClientRequestStrategy.java b/spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/WebTestClientRequestStrategy.java
index 5706c74f..59c7ff98 100644
--- a/spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/WebTestClientRequestStrategy.java
+++ b/spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/WebTestClientRequestStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -66,7 +66,7 @@ final class WebTestClientRequestStrategy extends RequestStrategySupport implemen
 				.expectStatus()
 				.isOk()
 				.expectHeader()
-				.contentType(MediaType.APPLICATION_JSON)
+				.contentTypeCompatibleWith(MediaType.APPLICATION_JSON)
 				.expectBody()
 				.returnResult();
 
diff --git a/spring-graphql-test/src/test/java/org/springframework/graphql/test/tester/WebGraphQlTesterTests.java b/spring-graphql-test/src/test/java/org/springframework/graphql/test/tester/WebGraphQlTesterTests.java
index c4d9e7f0..8f3fb893 100644
--- a/spring-graphql-test/src/test/java/org/springframework/graphql/test/tester/WebGraphQlTesterTests.java
+++ b/spring-graphql-test/src/test/java/org/springframework/graphql/test/tester/WebGraphQlTesterTests.java
@@ -211,7 +211,7 @@ public class WebGraphQlTesterTests {
 			sb.append("}");
 
 			MockResponse response = new MockResponse();
-			response.setHeader("Content-Type", "application/json");
+			response.setHeader("Content-Type", "application/json;charset=UTF-8"); // charset should be ignored if present
 			response.setBody(sb.toString());
 
 			this.server.enqueue(response);