Expose a WebTestClient with `@SpringBootTest`

This commit exposes a `WebTestClient` automatically in a reactive
integration test that uses an embedded web server. This is similar to
what we do with `TestRestTemplate` for servlet based integration tests.

Closes gh-8399

spring-boot-samples/spring-boot-sample-webflux/src/test/java/sample/webflux/SampleWebFluxApplicationIntegrationTests.java

@@ -16,18 +16,15 @@
 
 package sample.webflux;
 
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
 
-import org.springframework.boot.context.embedded.LocalServerPort;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.http.MediaType;
 import org.springframework.test.context.junit4.SpringRunner;
-import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.test.web.reactive.server.WebTestClient;
 
 /**
  * Basic integration tests for WebFlux application.
@@ -38,27 +35,16 @@ import org.springframework.web.reactive.function.client.WebClient;
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
 public class SampleWebFluxApplicationIntegrationTests {
 
-	@LocalServerPort
+	@Autowired
-	private int port;
+	private WebTestClient webClient;
-
-	private WebClient webClient;
-
-	@Before
-	public void setUp() throws Exception {
-		this.webClient = WebClient.create("http://localhost:" + this.port);
-	}
 
 	@Test
 	public void testWelcome() throws Exception {
-		Mono<String> body = this.webClient
+		this.webClient
 				.get().uri("/")
 				.accept(MediaType.TEXT_PLAIN)
 				.exchange()
-				.then(response -> response.bodyToMono(String.class));
+				.expectBody(String.class).value().isEqualTo("Hello World");
-
-		StepVerifier.create(body)
-				.expectNext("Hello World")
-				.verifyComplete();
 	}
 
 }

spring-boot-test/pom.xml

@@ -40,6 +40,11 @@
 			<artifactId>json-path</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>io.projectreactor.ipc</groupId>
+			<artifactId>reactor-netty</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 		<groupId>javax.servlet</groupId>
 			<artifactId>javax.servlet-api</artifactId>

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

@@ -0,0 +1,134 @@
+/*
+ * 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.web.reactive;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+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.context.embedded.AbstractConfigurableReactiveWebServer;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.ConfigurableApplicationContext;
+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;
+
+/**
+ * {@link ContextCustomizer} for {@link WebTestClient}.
+ *
+ * @author Stephane Nicoll
+ */
+class WebTestClientContextCustomizer implements ContextCustomizer {
+
+	@Override
+	public void customizeContext(ConfigurableApplicationContext context,
+			MergedContextConfiguration mergedConfig) {
+		SpringBootTest annotation = AnnotatedElementUtils.getMergedAnnotation(
+				mergedConfig.getTestClass(), SpringBootTest.class);
+		if (annotation.webEnvironment().isEmbedded()) {
+			registerWebTestClient(context);
+		}
+	}
+
+	private void registerWebTestClient(ConfigurableApplicationContext context) {
+		ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
+		if (beanFactory instanceof BeanDefinitionRegistry) {
+			registerWebTestClient(context, (BeanDefinitionRegistry) context);
+		}
+
+	}
+
+	private void registerWebTestClient(ConfigurableApplicationContext context,
+			BeanDefinitionRegistry registry) {
+		registry.registerBeanDefinition(WebTestClient.class.getName(),
+				new RootBeanDefinition(WebTestClientFactory.class));
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (obj == null || obj.getClass() != getClass()) {
+			return false;
+		}
+		return true;
+	}
+
+	/**
+	 * {@link FactoryBean} used to create and configure a {@link WebTestClient}.
+	 */
+	public static class WebTestClientFactory
+			implements FactoryBean<WebTestClient>, ApplicationContextAware {
+
+		private ApplicationContext applicationContext;
+
+		private WebTestClient object;
+
+		@Override
+		public void setApplicationContext(ApplicationContext applicationContext)
+				throws BeansException {
+			this.applicationContext = applicationContext;
+		}
+
+		@Override
+		public boolean isSingleton() {
+			return true;
+		}
+
+		@Override
+		public Class<?> getObjectType() {
+			return WebTestClient.class;
+		}
+
+		@Override
+		public WebTestClient getObject() throws Exception {
+			if (this.object == null) {
+				this.object = createWebTestClient();
+			}
+			return this.object;
+		}
+
+		private WebTestClient createWebTestClient() {
+			boolean sslEnabled = isSslEnabled(this.applicationContext);
+			String port = this.applicationContext.getEnvironment()
+					.getProperty("local.server.port", "8080");
+			String baseUrl = (sslEnabled ? "https" : "http") + "://localhost:" + port;
+			return WebTestClient.bindToServer().baseUrl(baseUrl).build();
+		}
+
+		private boolean isSslEnabled(ApplicationContext context) {
+			try {
+				AbstractConfigurableReactiveWebServer container = context
+						.getBean(AbstractConfigurableReactiveWebServer.class);
+				return container.getSsl() != null && container.getSsl().isEnabled();
+			}
+			catch (NoSuchBeanDefinitionException ex) {
+				return false;
+			}
+		}
+
+	}
+
+}

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

@@ -0,0 +1,52 @@
+/*
+ * 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.web.reactive;
+
+import java.util.List;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.test.context.ContextConfigurationAttributes;
+import org.springframework.test.context.ContextCustomizer;
+import org.springframework.test.context.ContextCustomizerFactory;
+import org.springframework.util.ClassUtils;
+
+/**
+ * {@link ContextCustomizerFactory} for {@code WebTestClient}.
+ *
+ * @author Stephane Nicoll
+ */
+public class WebTestClientContextCustomizerFactory implements ContextCustomizerFactory {
+
+	private static final String WEB_TEST_CLIENT_CLASS =
+			"org.springframework.web.reactive.function.client.WebClient";
+
+	@Override
+	public ContextCustomizer createContextCustomizer(Class<?> testClass,
+			List<ContextConfigurationAttributes> configAttributes) {
+		if (isWebClientPresent() && AnnotatedElementUtils.findMergedAnnotation(testClass,
+				SpringBootTest.class) != null) {
+			return new WebTestClientContextCustomizer();
+		}
+		return null;
+	}
+
+	private boolean isWebClientPresent() {
+		return ClassUtils.isPresent(WEB_TEST_CLIENT_CLASS, getClass().getClassLoader());
+	}
+
+}

spring-boot-test/src/main/resources/META-INF/spring.factories

@@ -3,7 +3,8 @@ org.springframework.test.context.ContextCustomizerFactory=\
 org.springframework.boot.test.context.ImportsContextCustomizerFactory,\
 org.springframework.boot.test.context.SpringBootTestContextCustomizerFactory,\
 org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizerFactory,\
-org.springframework.boot.test.mock.mockito.MockitoContextCustomizerFactory
+org.springframework.boot.test.mock.mockito.MockitoContextCustomizerFactory,\
+org.springframework.boot.test.web.reactive.WebTestClientContextCustomizerFactory
 
 # Test Execution Listeners
 org.springframework.test.context.TestExecutionListener=\

spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests.java

@@ -29,8 +29,8 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
 import org.springframework.http.server.reactive.HttpHandler;
+import org.springframework.test.web.reactive.server.WebTestClient;
 import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.client.RestTemplate;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -52,6 +52,9 @@ public abstract class AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests
 	@Autowired
 	private ReactiveWebApplicationContext context;
 
+	@Autowired
+	private WebTestClient webClient;
+
 	public ReactiveWebApplicationContext getContext() {
 		return this.context;
 	}
@@ -59,9 +62,19 @@ public abstract class AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests
 	@Test
 	public void runAndTestHttpEndpoint() {
 		assertThat(this.port).isNotEqualTo(8080).isNotEqualTo(0);
-		String body = new RestTemplate()
+		WebTestClient.bindToServer()
-				.getForObject("http://localhost:" + this.port + "/", String.class);
+				.baseUrl("http://localhost:" + this.port).build()
-		assertThat(body).isEqualTo("Hello World");
+				.get().uri("/")
+				.exchange()
+				.expectBody(String.class).value().isEqualTo("Hello World");
+	}
+
+	@Test
+	public void injectWebTestClient() {
+		this.webClient
+				.get().uri("/")
+				.exchange()
+				.expectBody(String.class).value().isEqualTo("Hello World");
 	}
 
 	@Test