Auto-configure codecs in WebTestClient

This commit applies what's been done in gh-9166 for WebFlux client and
server, but for the `WebTestClient` auto-configuration.

`WebTestClient` can be configured for mock or integration tests and this
change applies `CodecCustomizer` beans to the client being built.

Closes gh-9577

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/reactive/WebTestClientAutoConfiguration.java

@@ -16,12 +16,19 @@
 
 package org.springframework.boot.test.autoconfigure.web.reactive;
 
+import java.util.Collection;
+
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration;
+import org.springframework.boot.web.codec.CodecCustomizer;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.util.CollectionUtils;
+import org.springframework.web.reactive.function.client.ExchangeStrategies;
 import org.springframework.web.reactive.function.client.WebClient;
 
 /**
@@ -31,13 +38,32 @@ import org.springframework.web.reactive.function.client.WebClient;
  * @since 2.0.0
  */
 @Configuration
-@ConditionalOnClass({ WebClient.class, WebTestClient.class })
+@ConditionalOnClass({WebClient.class, WebTestClient.class})
+@AutoConfigureAfter(CodecsAutoConfiguration.class)
 public class WebTestClientAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
 	public WebTestClient webTestClient(ApplicationContext applicationContext) {
-		return WebTestClient.bindToApplicationContext(applicationContext).build();
+
+		WebTestClient.Builder clientBuilder = WebTestClient
+				.bindToApplicationContext(applicationContext).configureClient();
+		customizeWebTestClientCodecs(clientBuilder, applicationContext);
+		return clientBuilder.build();
+	}
+
+	private void customizeWebTestClientCodecs(WebTestClient.Builder clientBuilder,
+			ApplicationContext applicationContext) {
+
+		Collection<CodecCustomizer> codecCustomizers = applicationContext
+				.getBeansOfType(CodecCustomizer.class).values();
+		if (!CollectionUtils.isEmpty(codecCustomizers)) {
+			clientBuilder.exchangeStrategies(ExchangeStrategies.builder()
+					.codecs(codecs -> {
+						codecCustomizers.forEach(codecCustomizer -> codecCustomizer.customize(codecs));
+					})
+					.build());
+		}
 	}
 
 }

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/web/reactive/WebTestClientAutoConfigurationTests.java

+/*
+ * Copyright 2012-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.test.autoconfigure.web.reactive;
+
+import org.junit.After;
+import org.junit.Test;
+
+import org.springframework.boot.web.codec.CodecCustomizer;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.http.codec.CodecConfigurer;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.server.WebHandler;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link WebTestClientAutoConfiguration}
+ *
+ * @author Brian Clozel
+ */
+public class WebTestClientAutoConfigurationTests {
+
+	private AnnotationConfigApplicationContext context;
+
+	@After
+	public void close() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void shouldCustomizeClientCodecs() throws Exception {
+		load(CodecConfiguration.class);
+		WebTestClient webTestClient = this.context.getBean(WebTestClient.class);
+		CodecCustomizer codecCustomizer = this.context.getBean(CodecCustomizer.class);
+		assertThat(webTestClient).isNotNull();
+		verify(codecCustomizer).customize(any(CodecConfigurer.class));
+	}
+
+
+	private void load(Class<?>... config) {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(config);
+		ctx.register(WebTestClientAutoConfiguration.class);
+		ctx.refresh();
+		this.context = ctx;
+	}
+
+	@Configuration
+	static class BaseConfiguration {
+
+		@Bean
+		public WebHandler webHandler() {
+			return mock(WebHandler.class);
+		}
+	}
+
+	@Configuration
+	@Import(BaseConfiguration.class)
+	static class CodecConfiguration {
+
+		@Bean
+		public CodecCustomizer myCodecCustomizer() {
+			return mock(CodecCustomizer.class);
+		}
+
+	}
+
+}

spring-boot-test/pom.xml

@@ -105,6 +105,11 @@
 			<artifactId>spring-web</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-webflux</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>net.sourceforge.htmlunit</groupId>
 			<artifactId>htmlunit</artifactId>
@@ -162,11 +167,6 @@
 			<artifactId>spring-webmvc</artifactId>
 			<scope>test</scope>
 		</dependency>
-		<dependency>
-			<groupId>org.springframework</groupId>
-			<artifactId>spring-webflux</artifactId>
-			<scope>test</scope>
-		</dependency>
 	</dependencies>
 	<build>
 		<plugins>

spring-boot-test/src/main/java/org/springframework/boot/test/web/reactive/WebTestClientContextCustomizer.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.test.web.reactive;
 
+import java.util.Collection;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
@@ -23,6 +25,7 @@ import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.web.codec.CodecCustomizer;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@@ -31,6 +34,8 @@ import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.test.context.ContextCustomizer;
 import org.springframework.test.context.MergedContextConfiguration;
 import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.util.CollectionUtils;
+import org.springframework.web.reactive.function.client.ExchangeStrategies;
 
 /**
  * {@link ContextCustomizer} for {@link WebTestClient}.
@@ -115,7 +120,9 @@ class WebTestClientContextCustomizer implements ContextCustomizer {
 			String port = this.applicationContext.getEnvironment()
 					.getProperty("local.server.port", "8080");
 			String baseUrl = (sslEnabled ? "https" : "http") + "://localhost:" + port;
-			return WebTestClient.bindToServer().baseUrl(baseUrl).build();
+			WebTestClient.Builder builder = WebTestClient.bindToServer();
+			customizeWebTestClientCodecs(builder, this.applicationContext);
+			return builder.baseUrl(baseUrl).build();
 		}
 
 		private boolean isSslEnabled(ApplicationContext context) {
@@ -130,6 +137,18 @@ class WebTestClientContextCustomizer implements ContextCustomizer {
 			}
 		}
 
+		private void customizeWebTestClientCodecs(WebTestClient.Builder clientBuilder,
+				ApplicationContext context) {
+			Collection<CodecCustomizer> codecCustomizers = context.getBeansOfType(CodecCustomizer.class).values();
+			if (!CollectionUtils.isEmpty(codecCustomizers)) {
+				clientBuilder.exchangeStrategies(ExchangeStrategies.builder()
+						.codecs(codecs -> {
+							codecCustomizers.forEach(codecCustomizer -> codecCustomizer.customize(codecs));
+						})
+						.build());
+			}
+		}
+
 	}
 
 }