Use auto-configured JSON codecs for GraphQlTester

Prior to this commit, the auto-configured
`ExecutionGraphQlServiceTester` would use a default Jackson
`ObjectMapper` provided by the builder for its JSON
serialization/deserialization needs. Other testers, like the
`HttpGraphQlTester` are based on auto-configured components which
already use the auto-configured `ObjectMapper`.

This commit uses the newly introduced `encoder(Encoder<?>)` and
`decoder(Decoder<?>)` builder methods to configure custom JSON codecs
honoring the application configuration.

Closes gh-30646

spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/graphql/tester/GraphQlTesterAutoConfiguration.java

@@ -16,17 +16,23 @@
 
 package org.springframework.boot.test.autoconfigure.graphql.tester;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
 import graphql.GraphQL;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.graphql.GraphQlAutoConfiguration;
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.graphql.ExecutionGraphQlService;
 import org.springframework.graphql.test.tester.ExecutionGraphQlServiceTester;
 import org.springframework.graphql.test.tester.GraphQlTester;
+import org.springframework.http.MediaType;
+import org.springframework.http.codec.json.Jackson2JsonDecoder;
+import org.springframework.http.codec.json.Jackson2JsonEncoder;
 
 /**
  * Auto-configuration for {@link GraphQlTester}.
@@ -34,15 +40,23 @@ import org.springframework.graphql.test.tester.GraphQlTester;
  * @author Brian Clozel
  * @since 2.7.0
  */
-@AutoConfiguration(after = GraphQlAutoConfiguration.class)
+@AutoConfiguration(after = { JacksonAutoConfiguration.class, GraphQlAutoConfiguration.class })
 @ConditionalOnClass({ GraphQL.class, GraphQlTester.class })
 public class GraphQlTesterAutoConfiguration {
 
 	@Bean
 	@ConditionalOnBean(ExecutionGraphQlService.class)
 	@ConditionalOnMissingBean
-	public ExecutionGraphQlServiceTester graphQlTester(ExecutionGraphQlService graphQlService) {
-		return ExecutionGraphQlServiceTester.create(graphQlService);
+	public ExecutionGraphQlServiceTester graphQlTester(ExecutionGraphQlService graphQlService,
+			ObjectProvider<ObjectMapper> objectMapperProvider) {
+		ExecutionGraphQlServiceTester.Builder<?> builder = ExecutionGraphQlServiceTester.builder(graphQlService);
+		objectMapperProvider.ifAvailable(objectMapper -> {
+			final MediaType[] mediaTypes = new MediaType[] { MediaType.APPLICATION_JSON,
+					MediaType.APPLICATION_GRAPHQL };
+			builder.encoder(new Jackson2JsonEncoder(objectMapper, mediaTypes));
+			builder.decoder(new Jackson2JsonDecoder(objectMapper, mediaTypes));
+		});
+		return builder.build();
 	}
 
 }

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/graphql/tester/GraphQlTesterAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -19,6 +19,7 @@ package org.springframework.boot.test.autoconfigure.graphql.tester;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -35,8 +36,8 @@ import static org.mockito.Mockito.mock;
  */
 class GraphQlTesterAutoConfigurationTests {
 
-	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
-			.withConfiguration(AutoConfigurations.of(GraphQlTesterAutoConfiguration.class));
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().withConfiguration(
+			AutoConfigurations.of(JacksonAutoConfiguration.class, GraphQlTesterAutoConfiguration.class));
 
 	@Test
 	void shouldNotContributeTesterIfGraphQlServiceNotPresent() {