Call complete() on MockAsyncContext after dispatch

Issue: SPR-13615

spring-test/src/main/java/org/springframework/test/web/servlet/MockMvc.java

@@ -18,6 +18,7 @@ package org.springframework.test.web.servlet;
 
 import java.util.ArrayList;
 import java.util.List;
+import javax.servlet.DispatcherType;
 import javax.servlet.Filter;
 import javax.servlet.ServletContext;
 
@@ -147,14 +148,18 @@ public final class MockMvc {
 		final MvcResult mvcResult = new DefaultMvcResult(request, response);
 		request.setAttribute(MVC_RESULT_ATTRIBUTE, mvcResult);
 
-		// [SPR-13217] Simulate RequestContextFilter to ensure that RequestAttributes are
-		// populated before filters are invoked.
 		RequestAttributes previousAttributes = RequestContextHolder.getRequestAttributes();
 		RequestContextHolder.setRequestAttributes(new ServletRequestAttributes(request, response));
 
 		MockFilterChain filterChain = new MockFilterChain(this.servlet, this.filters);
 		filterChain.doFilter(request, response);
 
+		if (DispatcherType.ASYNC.equals(request.getDispatcherType()) &&
+				request.getAsyncContext() != null & !request.isAsyncStarted()) {
+
+			request.getAsyncContext().complete();
+		}
+
 		applyDefaultResultActions(mvcResult);
 
 		RequestContextHolder.setRequestAttributes(previousAttributes);

spring-test/src/main/java/org/springframework/test/web/servlet/request/MockMvcRequestBuilders.java

@@ -17,6 +17,7 @@
 package org.springframework.test.web.servlet.request;
 
 import java.net.URI;
+import javax.servlet.DispatcherType;
 import javax.servlet.ServletContext;
 
 import org.springframework.http.HttpMethod;
@@ -237,6 +238,7 @@ public abstract class MockMvcRequestBuilders {
 			@Override
 			public MockHttpServletRequest buildRequest(ServletContext servletContext) {
 				MockHttpServletRequest request = mvcResult.getRequest();
+				request.setDispatcherType(DispatcherType.ASYNC);
 				request.setAsyncStarted(false);
 				return request;
 			}