Improve testing of ReactiveWebServerApplicationContext

Closes gh-21314

Author: wilkinsona

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/context/ReactiveWebServerApplicationContextTests.java

@@ -0,0 +1,189 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.reactive.context;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.List;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.boot.availability.AvailabilityChangeEvent;
+import org.springframework.boot.availability.ReadinessState;
+import org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer;
+import org.springframework.boot.web.reactive.server.MockReactiveWebServerFactory;
+import org.springframework.context.ApplicationContextException;
+import org.springframework.context.ApplicationEvent;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.event.ContextClosedEvent;
+import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.http.server.reactive.HttpHandler;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link ReactiveWebServerApplicationContext}.
+ *
+ * @author Andy Wilkinson
+ */
+class ReactiveWebServerApplicationContextTests {
+
+	private ReactiveWebServerApplicationContext context = new ReactiveWebServerApplicationContext();
+
+	@AfterEach
+	void cleanUp() {
+		this.context.close();
+	}
+
+	@Test
+	void whenThereIsNoWebServerFactoryBeanThenContextRefreshWillFail() {
+		assertThatExceptionOfType(ApplicationContextException.class).isThrownBy(() -> this.context.refresh())
+				.withMessageContaining(
+						"Unable to start ReactiveWebApplicationContext due to missing ReactiveWebServerFactory bean");
+	}
+
+	@Test
+	void whenThereIsNoHttpHandlerBeanThenContextRefreshWillFail() {
+		addWebServerFactoryBean();
+		assertThatExceptionOfType(ApplicationContextException.class).isThrownBy(() -> this.context.refresh())
+				.withMessageContaining("Unable to start ReactiveWebApplicationContext due to missing HttpHandler bean");
+	}
+
+	@Test
+	void whenThereAreMultipleWebServerFactoryBeansThenContextRefreshWillFail() {
+		addWebServerFactoryBean();
+		addWebServerFactoryBean("anotherWebServerFactory");
+		assertThatExceptionOfType(ApplicationContextException.class).isThrownBy(() -> this.context.refresh())
+				.withMessageContaining(
+						"Unable to start ReactiveWebApplicationContext due to multiple ReactiveWebServerFactory beans");
+	}
+
+	@Test
+	void whenThereAreMultipleHttpHandlerBeansThenContextRefreshWillFail() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean("httpHandler1");
+		addHttpHandlerBean("httpHandler2");
+		assertThatExceptionOfType(ApplicationContextException.class).isThrownBy(() -> this.context.refresh())
+				.withMessageContaining(
+						"Unable to start ReactiveWebApplicationContext due to multiple HttpHandler beans");
+	}
+
+	@Test
+	void whenContextIsRefreshedThenReactiveWebServerInitializedEventIsPublished() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean();
+		TestApplicationListener listener = new TestApplicationListener();
+		this.context.addApplicationListener(listener);
+		this.context.refresh();
+		List<ApplicationEvent> events = listener.receivedEvents();
+		assertThat(events).hasSize(2).extracting("class").containsExactly(ContextRefreshedEvent.class,
+				ReactiveWebServerInitializedEvent.class);
+		ReactiveWebServerInitializedEvent initializedEvent = (ReactiveWebServerInitializedEvent) events.get(1);
+		assertThat(initializedEvent.getSource().getPort()).isGreaterThanOrEqualTo(0);
+		assertThat(initializedEvent.getApplicationContext()).isEqualTo(this.context);
+	}
+
+	@Test
+	void whenContextIsRefreshedThenLocalServerPortIsAvailableFromTheEnvironment() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean();
+		new ServerPortInfoApplicationContextInitializer().initialize(this.context);
+		this.context.refresh();
+		ConfigurableEnvironment environment = this.context.getEnvironment();
+		assertThat(environment.containsProperty("local.server.port")).isTrue();
+		assertThat(environment.getProperty("local.server.port")).isEqualTo("8080");
+	}
+
+	@Test
+	void whenContextIsClosedThenWebServerIsStopped() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean();
+		this.context.refresh();
+		MockReactiveWebServerFactory factory = this.context.getBean(MockReactiveWebServerFactory.class);
+		this.context.close();
+		verify(factory.getWebServer()).stop();
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	void whenContextIsClosedThenApplicationAvailabilityChangesToRefusingTraffic() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean();
+		TestApplicationListener listener = new TestApplicationListener();
+		this.context.refresh();
+		this.context.addApplicationListener(listener);
+		this.context.close();
+		List<ApplicationEvent> events = listener.receivedEvents();
+		assertThat(events).hasSize(2).extracting("class").contains(AvailabilityChangeEvent.class,
+				ContextClosedEvent.class);
+		assertThat(((AvailabilityChangeEvent<ReadinessState>) events.get(0)).getState())
+				.isEqualTo(ReadinessState.REFUSING_TRAFFIC);
+	}
+
+	@Test
+	void whenTheContextIsRefreshedThenASubsequentRefreshAttemptWillFail() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean();
+		this.context.refresh();
+		assertThatIllegalStateException().isThrownBy(() -> this.context.refresh())
+				.withMessageContaining("multiple refresh attempts");
+	}
+
+	private void addHttpHandlerBean() {
+		addHttpHandlerBean("httpHandler");
+	}
+
+	private void addHttpHandlerBean(String beanName) {
+		this.context.registerBeanDefinition(beanName,
+				new RootBeanDefinition(HttpHandler.class, () -> (request, response) -> null));
+	}
+
+	private void addWebServerFactoryBean() {
+		addWebServerFactoryBean("webServerFactory");
+	}
+
+	private void addWebServerFactoryBean(String beanName) {
+		this.context.registerBeanDefinition(beanName, new RootBeanDefinition(MockReactiveWebServerFactory.class));
+	}
+
+	static class TestApplicationListener implements ApplicationListener<ApplicationEvent> {
+
+		private Deque<ApplicationEvent> events = new ArrayDeque<>();
+
+		@Override
+		public void onApplicationEvent(ApplicationEvent event) {
+			this.events.add(event);
+		}
+
+		List<ApplicationEvent> receivedEvents() {
+			List<ApplicationEvent> receivedEvents = new ArrayList<>();
+			while (!this.events.isEmpty()) {
+				receivedEvents.add(this.events.pollFirst());
+			}
+			return receivedEvents;
+		}
+
+	}
+
+}