Add test for combining @Controller with RouterFunctions

This commit adds a test for combining RouterFunctions with a
@Controller.

Issue: SPR-15521

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/DispatcherHandlerIntegrationTests.java

@@ -17,17 +17,11 @@
 package org.springframework.web.reactive.function.server;
 
 import java.util.List;
-import java.util.Locale;
-import java.util.Optional;
-import java.util.function.Function;
-import java.util.function.Supplier;
-import java.util.stream.Stream;
 
 import org.junit.Test;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -35,18 +29,19 @@ import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
-import org.springframework.http.codec.HttpMessageReader;
-import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.server.reactive.AbstractHttpHandlerIntegrationTests;
 import org.springframework.http.server.reactive.HttpHandler;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.reactive.DispatcherHandler;
 import org.springframework.web.reactive.HandlerAdapter;
 import org.springframework.web.reactive.HandlerMapping;
+import org.springframework.web.reactive.config.EnableWebFlux;
 import org.springframework.web.reactive.config.WebFluxConfigurationSupport;
 import org.springframework.web.reactive.function.server.support.HandlerFunctionAdapter;
 import org.springframework.web.reactive.function.server.support.ServerResponseResultHandler;
-import org.springframework.web.reactive.result.view.ViewResolver;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
 
 import static org.junit.Assert.*;
@@ -56,7 +51,7 @@ import static org.springframework.web.reactive.function.server.RouterFunctions.r
 
 /**
  * Tests the use of {@link HandlerFunction} and {@link RouterFunction} in a
- * {@link DispatcherHandler}.
+ * {@link DispatcherHandler}, combined with {@link Controller}s.
  *
  * @author Arjen Poutsma
  */
@@ -103,6 +98,15 @@ public class DispatcherHandlerIntegrationTests extends AbstractHttpHandlerIntegr
 		assertEquals("Jane", body.get(1).getName());
 	}
 
+	@Test
+	public void controller() throws Exception {
+		ResponseEntity<Person> result =
+				this.restTemplate.getForEntity("http://localhost:" + this.port + "/controller", Person.class);
+
+		assertEquals(HttpStatus.OK, result.getStatusCode());
+		assertEquals("John", result.getBody().getName());
+	}
+
 
 	@Configuration
 	static class TestConfiguration extends WebFluxConfigurationSupport {
@@ -113,45 +117,22 @@ public class DispatcherHandlerIntegrationTests extends AbstractHttpHandlerIntegr
 		}
 
 		@Bean
-		public HandlerAdapter handlerAdapter() {
-			return new HandlerFunctionAdapter();
+		public PersonController personController() {
+			return new PersonController();
 		}
 
 		@Bean
-		public HandlerMapping handlerMapping(RouterFunction<?> routerFunction,
-				ApplicationContext applicationContext) {
-
-			return RouterFunctions.toHandlerMapping(routerFunction,
-					new HandlerStrategies() {
-						@Override
-						public Supplier<Stream<HttpMessageReader<?>>> messageReaders() {
-							return () -> serverCodecConfigurer().getReaders().stream()
-									.map(reader -> (HttpMessageReader<?>) reader);
-						}
-
-						@Override
-						public Supplier<Stream<HttpMessageWriter<?>>> messageWriters() {
-							return () -> serverCodecConfigurer().getWriters().stream()
-									.map(writer -> (HttpMessageWriter<?>) writer);
-						}
-
-						@Override
-						public Supplier<Stream<ViewResolver>> viewResolvers() {
-							return Stream::empty;
-						}
-
-						@Override
-						public Supplier<Function<ServerRequest, Optional<Locale>>> localeResolver() {
-							return () -> DefaultHandlerStrategiesBuilder.DEFAULT_LOCALE_RESOLVER;
-						}
-					});
+		public HandlerAdapter handlerAdapter() {
+			return new HandlerFunctionAdapter();
 		}
 
 		@Bean
-		public RouterFunction<?> routerFunction() {
+		public HandlerMapping handlerMapping() {
+
 			PersonHandler personHandler = personHandler();
-			return route(RequestPredicates.GET("/mono"), personHandler::mono)
-					.and(route(RequestPredicates.GET("/flux"), personHandler::flux));
+			return RouterFunctions.toHandlerMapping(
+					route(RequestPredicates.GET("/mono"), personHandler::mono)
+							.and(route(RequestPredicates.GET("/flux"), personHandler::flux)));
 		}
 
 		@Bean
@@ -177,6 +158,16 @@ public class DispatcherHandlerIntegrationTests extends AbstractHttpHandlerIntegr
 
 	}
 
+	@Controller
+	private static class PersonController {
+
+		@RequestMapping("/controller")
+		@ResponseBody
+		public Mono<Person> controller() {
+			return Mono.just(new Person("John"));
+		}
+	}
+
 	private static class Person {
 
 		private String name;