Call ServletContextListener.contextDestroyed() when Undertow is stopped

Previously, when the embedded Undertow container was stopped, the
servlet deployment was stopped but it was not undeployed. This meant
that contextDestroyed() callback of any registered
ServletContextListeners was not called.

This commit updates UndertowEmbeddedServletContainer to call undeploy
on the deployment manager in addition to the existing call to stop.
Undeploying the servlet deployment calls Undertow to drive the
contextDestroyed callback on any registered ServletContextListeners.

Closes gh-13134

spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainer.java

@@ -333,6 +333,7 @@ public class UndertowEmbeddedServletContainer implements EmbeddedServletContaine
 			this.started = false;
 			try {
 				this.manager.stop();
+				this.manager.undeploy();
 				this.undertow.stop();
 			}
 			catch (Exception ex) {

spring-boot/src/test/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactoryTests.java

@@ -55,6 +55,8 @@ import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLException;
 import javax.servlet.GenericServlet;
 import javax.servlet.ServletContext;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
@@ -110,6 +112,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.junit.Assert.fail;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyObject;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
@@ -1035,6 +1038,26 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 		assertThat(documentRoot).isNull();
 	}
 
+	@Test
+	public void servletContextListenerContextDestroyedIsCalledWhenContainerIsStopped()
+			throws Exception {
+		final ServletContextListener listener = mock(ServletContextListener.class);
+		AbstractEmbeddedServletContainerFactory factory = getFactory();
+		this.container = factory
+				.getEmbeddedServletContainer(new ServletContextInitializer() {
+
+					@Override
+					public void onStartup(ServletContext servletContext)
+							throws ServletException {
+						servletContext.addListener(listener);
+					}
+
+				});
+		this.container.start();
+		this.container.stop();
+		verify(listener).contextDestroyed(any(ServletContextEvent.class));
+	}
+
 	protected abstract void addConnector(int port,
 			AbstractEmbeddedServletContainerFactory factory);