Refactor @ResponseBody and ResponseEntity tests

Introduce separate test classes for each base class in the hierarchy
above @ResponseBody and ResponseEntity result handlers.

Also start porting existing unit test cases for @ResponseBody and
ResponseEntity return value handlers.

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/ContentNegotiatingResultHandlerSupport.java

@@ -126,7 +126,7 @@ public abstract class ContentNegotiatingResultHandlerSupport implements Ordered
 	}
 
 	private List<MediaType> getAcceptableTypes(ServerWebExchange exchange) {
-		List<MediaType> mediaTypes = this.contentTypeResolver.resolveMediaTypes(exchange);
+		List<MediaType> mediaTypes = getContentTypeResolver().resolveMediaTypes(exchange);
 		return (mediaTypes.isEmpty() ? Collections.singletonList(MediaType.ALL) : mediaTypes);
 	}
 

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageConverterResultHandler.java

@@ -19,6 +19,7 @@ import java.util.List;
 import java.util.stream.Collectors;
 
 import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.ResolvableType;
@@ -82,16 +83,22 @@ public abstract class AbstractMessageConverterResultHandler extends ContentNegot
 				publisher = Mono.empty();
 			}
 			elementType = bodyType.getGeneric(0);
-			if (Void.class.equals(elementType.getRawClass())) {
-				return Mono.from((Publisher<Void>) publisher);
-			}
 		}
 		else {
 			publisher = Mono.justOrEmpty(body);
 			elementType = bodyType;
 		}
 
+		if (Void.class.equals(elementType.getRawClass())) {
+			return Mono.from((Publisher<Void>) publisher);
+		}
+
 		List<MediaType> producibleTypes = getProducibleMediaTypes(elementType);
+		if (producibleTypes.isEmpty()) {
+			return Mono.error(new IllegalStateException(
+					"No converter for return value type: " + elementType));
+		}
+
 		MediaType bestMediaType = selectMediaType(exchange, producibleTypes);
 
 		if (bestMediaType != null) {

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandler.java

@@ -104,7 +104,7 @@ public class ResponseEntityResultHandler extends AbstractMessageConverterResultH
 
 			if (!entityHeaders.isEmpty()) {
 				entityHeaders.entrySet().stream()
-						.filter(entry -> responseHeaders.containsKey(entry.getKey()))
+						.filter(entry -> !responseHeaders.containsKey(entry.getKey()))
 						.forEach(entry -> responseHeaders.put(entry.getKey(), entry.getValue()));
 			}
 

spring-web-reactive/src/test/java/org/springframework/web/reactive/result/ContentNegotiatingResultHandlerSupportTests.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright 2002-2016 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.web.reactive.result;
+
+import java.net.URI;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.convert.support.GenericConversionService;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.server.reactive.MockServerHttpRequest;
+import org.springframework.http.server.reactive.MockServerHttpResponse;
+import org.springframework.web.reactive.accept.FixedContentTypeResolver;
+import org.springframework.web.reactive.accept.HeaderContentTypeResolver;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.springframework.http.MediaType.ALL;
+import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8;
+import static org.springframework.http.MediaType.APPLICATION_OCTET_STREAM;
+import static org.springframework.http.MediaType.IMAGE_GIF;
+import static org.springframework.http.MediaType.IMAGE_JPEG;
+import static org.springframework.http.MediaType.IMAGE_PNG;
+import static org.springframework.http.MediaType.TEXT_PLAIN;
+import static org.springframework.web.reactive.HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE;
+
+/**
+ * Unit tests for {@link ContentNegotiatingResultHandlerSupport}.
+ * @author Rossen Stoyanchev
+ */
+public class ContentNegotiatingResultHandlerSupportTests {
+
+	private TestHandlerSupport handlerSupport;
+
+	private MockServerHttpRequest request;
+
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.handlerSupport = new TestHandlerSupport();
+		this.request = new MockServerHttpRequest(HttpMethod.GET, new URI("/path"));
+		this.exchange = new DefaultServerWebExchange(
+				this.request, new MockServerHttpResponse(), mock(WebSessionManager.class));
+	}
+
+
+	@Test
+	public void usesContentTypeResolver() throws Exception {
+		RequestedContentTypeResolver resolver = new FixedContentTypeResolver(IMAGE_GIF);
+		TestHandlerSupport handlerSupport = new TestHandlerSupport(resolver);
+
+		List<MediaType> mediaTypes = Arrays.asList(IMAGE_JPEG, IMAGE_GIF, IMAGE_PNG);
+		MediaType actual = handlerSupport.selectMediaType(this.exchange, mediaTypes);
+
+		assertEquals(IMAGE_GIF, actual);
+	}
+
+	@Test
+	public void producibleMediaTypesRequestAttribute() throws Exception {
+		Set<MediaType> producible = Collections.singleton(IMAGE_GIF);
+		this.exchange.getAttributes().put(PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE, producible);
+
+		List<MediaType> mediaTypes = Arrays.asList(IMAGE_JPEG, IMAGE_GIF, IMAGE_PNG);
+		MediaType actual = handlerSupport.selectMediaType(this.exchange, mediaTypes);
+
+		assertEquals(IMAGE_GIF, actual);
+	}
+
+	@Test  // SPR-9160
+	public void sortsByQuality() throws Exception {
+		this.request.getHeaders().add("Accept", "text/plain; q=0.5, application/json");
+
+		List<MediaType> mediaTypes = Arrays.asList(TEXT_PLAIN, APPLICATION_JSON_UTF8);
+		MediaType actual = this.handlerSupport.selectMediaType(this.exchange, mediaTypes);
+
+		assertEquals(APPLICATION_JSON_UTF8, actual);
+	}
+
+	@Test
+	public void charsetFromAcceptHeader() throws Exception {
+		MediaType text8859 = MediaType.parseMediaType("text/plain;charset=ISO-8859-1");
+		MediaType textUtf8 = MediaType.parseMediaType("text/plain;charset=UTF-8");
+
+		this.request.getHeaders().setAccept(Collections.singletonList(text8859));
+		MediaType actual = this.handlerSupport.selectMediaType(this.exchange, Collections.singletonList(textUtf8));
+
+		assertEquals(text8859, actual);
+	}
+
+	@Test // SPR-12894
+	public void noConcreteMediaType() throws Exception {
+		List<MediaType> producible = Collections.singletonList(ALL);
+		MediaType actual = this.handlerSupport.selectMediaType(this.exchange, producible);
+
+		assertEquals(APPLICATION_OCTET_STREAM, actual);
+	}
+
+
+
+
+	private static class TestHandlerSupport extends ContentNegotiatingResultHandlerSupport {
+
+		protected TestHandlerSupport() {
+			this(new HeaderContentTypeResolver());
+		}
+
+		public TestHandlerSupport(RequestedContentTypeResolver contentTypeResolver) {
+			super(new GenericConversionService(), contentTypeResolver);
+		}
+	}
+
+}

spring-web-reactive/src/test/java/org/springframework/web/reactive/result/method/annotation/MessageConverterResultHandlerTests.java

@@ -0,0 +1,155 @@
+/*
+ * Copyright 2002-2016 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.web.reactive.result.method.annotation;
+
+import java.io.ByteArrayOutputStream;
+import java.io.OutputStream;
+import java.net.URI;
+import java.nio.charset.Charset;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.test.TestSubscriber;
+import rx.Observable;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.codec.Decoder;
+import org.springframework.core.codec.Encoder;
+import org.springframework.core.codec.support.ByteBufferDecoder;
+import org.springframework.core.codec.support.ByteBufferEncoder;
+import org.springframework.core.codec.support.JacksonJsonDecoder;
+import org.springframework.core.codec.support.JacksonJsonEncoder;
+import org.springframework.core.codec.support.Jaxb2Decoder;
+import org.springframework.core.codec.support.Jaxb2Encoder;
+import org.springframework.core.codec.support.JsonObjectDecoder;
+import org.springframework.core.codec.support.StringDecoder;
+import org.springframework.core.codec.support.StringEncoder;
+import org.springframework.core.convert.support.GenericConversionService;
+import org.springframework.core.convert.support.ReactiveStreamsToCompletableFutureConverter;
+import org.springframework.core.convert.support.ReactiveStreamsToRxJava1Converter;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.buffer.support.DataBufferTestUtils;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.converter.reactive.CodecHttpMessageConverter;
+import org.springframework.http.converter.reactive.HttpMessageConverter;
+import org.springframework.http.converter.reactive.ResourceHttpMessageConverter;
+import org.springframework.http.server.reactive.MockServerHttpRequest;
+import org.springframework.http.server.reactive.MockServerHttpResponse;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.util.ObjectUtils;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Unit tests for {@link AbstractMessageConverterResultHandler}.
+ * @author Rossen Stoyanchev
+ */
+public class MessageConverterResultHandlerTests {
+
+	private AbstractMessageConverterResultHandler resultHandler;
+
+	private MockServerHttpResponse response = new MockServerHttpResponse();
+
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.resultHandler = createResultHandler();
+		ServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, new URI("/path"));
+		this.exchange = new DefaultServerWebExchange(request, this.response, mock(WebSessionManager.class));
+	}
+
+
+	@Test // SPR-12894
+	@Ignore // GH # 121
+	public void useDefaultContentType() throws Exception {
+		Object body = new ByteArrayResource("body".getBytes("UTF-8"));
+		ResolvableType bodyType = ResolvableType.forType(Resource.class);
+		this.resultHandler.writeBody(this.exchange, body, bodyType).block(Duration.ofSeconds(5));
+
+		assertEquals("image/jpeg", this.response.getHeaders().getFirst("Content-Type"));
+		TestSubscriber.subscribe(this.response.getBody())
+				.assertValuesWith(buf -> assertEquals("body",
+						DataBufferTestUtils.dumpString(buf, Charset.forName("UTF-8"))));
+	}
+
+	@Test
+	public void voidReturnType() throws Exception {
+		testVoidReturnType(null, ResolvableType.forType(Void.class));
+		testVoidReturnType(Mono.empty(), ResolvableType.forClassWithGenerics(Mono.class, Void.class));
+		testVoidReturnType(Flux.empty(), ResolvableType.forClassWithGenerics(Flux.class, Void.class));
+		testVoidReturnType(Observable.empty(), ResolvableType.forClassWithGenerics(Observable.class, Void.class));
+	}
+
+	private void testVoidReturnType(Object body, ResolvableType bodyType) {
+		this.resultHandler.writeBody(this.exchange, body, bodyType).block(Duration.ofSeconds(5));
+
+		assertNull(this.response.getHeaders().get("Content-Type"));
+		assertNull(this.response.getBody());
+	}
+
+	@Test // SPR-13135
+	public void unsupportedReturnType() throws Exception {
+		ByteArrayOutputStream body = new ByteArrayOutputStream();
+		ResolvableType bodyType = ResolvableType.forType(OutputStream.class);
+
+		HttpMessageConverter<?> converter = new CodecHttpMessageConverter<>(new ByteBufferEncoder());
+		Mono<Void> mono = createResultHandler(converter).writeBody(this.exchange, body, bodyType);
+
+		TestSubscriber.subscribe(mono).assertError(IllegalStateException.class);
+	}
+
+
+	private AbstractMessageConverterResultHandler createResultHandler(HttpMessageConverter<?>... converters) {
+		List<HttpMessageConverter<?>> converterList;
+		if (ObjectUtils.isEmpty(converters)) {
+			converterList = new ArrayList<>();
+			converterList.add(new CodecHttpMessageConverter<>(new ByteBufferEncoder()));
+			converterList.add(new CodecHttpMessageConverter<>(new StringEncoder()));
+			converterList.add(new ResourceHttpMessageConverter());
+			converterList.add(new CodecHttpMessageConverter<>(new Jaxb2Encoder()));
+			converterList.add(new CodecHttpMessageConverter<>(new JacksonJsonEncoder()));
+		}
+		else {
+			converterList = Arrays.asList(converters);
+		}
+
+		GenericConversionService service = new GenericConversionService();
+		service.addConverter(new ReactiveStreamsToCompletableFutureConverter());
+		service.addConverter(new ReactiveStreamsToRxJava1Converter());
+
+		RequestedContentTypeResolver resolver = new RequestedContentTypeResolverBuilder().build();
+
+		return new AbstractMessageConverterResultHandler(converterList, service, resolver) {};
+	}
+
+}

spring-web-reactive/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java

@@ -17,143 +17,154 @@
 package org.springframework.web.reactive.result.method.annotation;
 
 import java.net.URI;
-import java.net.URISyntaxException;
+import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
-import java.util.Set;
-import java.util.stream.Collectors;
 
+import org.junit.Before;
 import org.junit.Test;
-import org.reactivestreams.Publisher;
 
 import org.springframework.core.ResolvableType;
-import org.springframework.core.codec.Encoder;
+import org.springframework.core.codec.support.ByteBufferEncoder;
 import org.springframework.core.codec.support.JacksonJsonEncoder;
+import org.springframework.core.codec.support.Jaxb2Encoder;
 import org.springframework.core.codec.support.StringEncoder;
 import org.springframework.core.convert.support.DefaultConversionService;
+import org.springframework.core.convert.support.GenericConversionService;
+import org.springframework.core.convert.support.ReactiveStreamsToCompletableFutureConverter;
+import org.springframework.core.convert.support.ReactiveStreamsToRxJava1Converter;
 import org.springframework.http.HttpMethod;
-import org.springframework.http.MediaType;
 import org.springframework.http.converter.reactive.CodecHttpMessageConverter;
 import org.springframework.http.converter.reactive.HttpMessageConverter;
+import org.springframework.http.converter.reactive.ResourceHttpMessageConverter;
 import org.springframework.http.server.reactive.MockServerHttpRequest;
 import org.springframework.http.server.reactive.MockServerHttpResponse;
 import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.stereotype.Controller;
 import org.springframework.ui.ExtendedModelMap;
+import org.springframework.util.ObjectUtils;
 import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.method.HandlerMethod;
-import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.HandlerResult;
-import org.springframework.web.reactive.HandlerResultHandler;
-import org.springframework.web.reactive.accept.FixedContentTypeResolver;
-import org.springframework.web.reactive.accept.HeaderContentTypeResolver;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.adapter.DefaultServerWebExchange;
 import org.springframework.web.server.session.WebSessionManager;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
-import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8;
 
 
 /**
  * Unit tests for {@link ResponseBodyResultHandler}.
+ *
+ * consider whether the logic under test is in a parent class, then see:
+ * <ul>
+ * 	<li>{@code MessageConverterResultHandlerTests},
+ *  <li>{@code ContentNegotiatingResultHandlerSupportTests}
+ * </ul>
  * @author Sebastien Deleuze
  * @author Rossen Stoyanchev
  */
 public class ResponseBodyResultHandlerTests {
 
+	private ResponseBodyResultHandler resultHandler;
+
+	private MockServerHttpResponse response = new MockServerHttpResponse();
+
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.resultHandler = createHandler();
+		ServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, new URI("/path"));
+		this.exchange = new DefaultServerWebExchange(request, this.response, mock(WebSessionManager.class));
+	}
+
+
+	private ResponseBodyResultHandler createHandler(HttpMessageConverter<?>... converters) {
+		List<HttpMessageConverter<?>> converterList;
+		if (ObjectUtils.isEmpty(converters)) {
+			converterList = new ArrayList<>();
+			converterList.add(new CodecHttpMessageConverter<>(new ByteBufferEncoder()));
+			converterList.add(new CodecHttpMessageConverter<>(new StringEncoder()));
+			converterList.add(new ResourceHttpMessageConverter());
+			converterList.add(new CodecHttpMessageConverter<>(new Jaxb2Encoder()));
+			converterList.add(new CodecHttpMessageConverter<>(new JacksonJsonEncoder()));
+		}
+		else {
+			converterList = Arrays.asList(converters);
+		}
+		GenericConversionService service = new GenericConversionService();
+		service.addConverter(new ReactiveStreamsToCompletableFutureConverter());
+		service.addConverter(new ReactiveStreamsToRxJava1Converter());
+		RequestedContentTypeResolver resolver = new RequestedContentTypeResolverBuilder().build();
+
+		return new ResponseBodyResultHandler(converterList, new DefaultConversionService(), resolver);
+	}
 
 	@Test
 	public void supports() throws NoSuchMethodException {
-		ResponseBodyResultHandler handler = createHandler(new StringEncoder());
 		TestController controller = new TestController();
+		testSupports(controller, "handleReturningString", true);
+		testSupports(controller, "handleReturningVoid", true);
+		testSupports(controller, "doWork", false);
 
-		HandlerMethod hm = new HandlerMethod(controller, TestController.class.getMethod("notAnnotated"));
+		TestRestController restController = new TestRestController();
+		testSupports(restController, "handleReturningString", true);
+		testSupports(restController, "handleReturningVoid", true);
+	}
+
+	private void testSupports(Object controller, String method, boolean result) throws NoSuchMethodException {
+		HandlerMethod hm = handlerMethod(controller, method);
 		ResolvableType type = ResolvableType.forMethodParameter(hm.getReturnType());
-		assertFalse(handler.supports(new HandlerResult(hm, null, type, new ExtendedModelMap())));
+		HandlerResult handlerResult = new HandlerResult(hm, null, type, new ExtendedModelMap());
-
+		assertEquals(result, this.resultHandler.supports(handlerResult));
-		hm = new HandlerMethod(controller, TestController.class.getMethod("publisherString"));
-		type = ResolvableType.forMethodParameter(hm.getReturnType());
-		assertTrue(handler.supports(new HandlerResult(hm, null, type, new ExtendedModelMap())));
-
-		hm = new HandlerMethod(controller, TestController.class.getMethod("publisherVoid"));
-		type = ResolvableType.forMethodParameter(hm.getReturnType());
-		assertTrue(handler.supports(new HandlerResult(hm, null, type, new ExtendedModelMap())));
 	}
 
 	@Test
 	public void defaultOrder() throws Exception {
-		ResponseBodyResultHandler handler = createHandler(new StringEncoder());
+		assertEquals(100, this.resultHandler.getOrder());
-		assertEquals(100, handler.getOrder());
-	}
-
-	@Test
-	public void usesContentTypeResolver() throws Exception {
-		RequestedContentTypeResolver resolver = new FixedContentTypeResolver(APPLICATION_JSON_UTF8);
-		HandlerResultHandler handler = createHandler(resolver, new StringEncoder(), new JacksonJsonEncoder());
-
-		ServerWebExchange exchange = createExchange("/foo");
-		HandlerResult result = new HandlerResult(new Object(), "fooValue", ResolvableType.forClass(String.class));
-		handler.handleResult(exchange, result).block();
-
-		assertEquals(APPLICATION_JSON_UTF8, exchange.getResponse().getHeaders().getContentType());
-	}
-
-	@Test
-	public void detectsProducibleMediaTypesAttribute() throws Exception {
-		ServerWebExchange exchange = createExchange("/foo");
-		Set<MediaType> mediaTypes = Collections.singleton(MediaType.APPLICATION_JSON);
-		exchange.getAttributes().put(HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE, mediaTypes);
-
-		HandlerResultHandler handler = createHandler(new StringEncoder(), new JacksonJsonEncoder());
-
-		HandlerResult result = new HandlerResult(new Object(), "fooValue", ResolvableType.forClass(String.class));
-		handler.handleResult(exchange, result).block();
-
-		assertEquals(MediaType.APPLICATION_JSON, exchange.getResponse().getHeaders().getContentType());
 	}
 
 
-	private ResponseBodyResultHandler createHandler(Encoder<?>... encoders) {
+	private HandlerMethod handlerMethod(Object controller, String method) throws NoSuchMethodException {
-		return createHandler(new HeaderContentTypeResolver(), encoders);
+		return new HandlerMethod(controller, controller.getClass().getMethod(method));
-	}
-
-	private ResponseBodyResultHandler createHandler(RequestedContentTypeResolver resolver,
-			Encoder<?>... encoders) {
-
-		List<HttpMessageConverter<?>> converters = Arrays.stream(encoders)
-				.map(encoder -> new CodecHttpMessageConverter<>(encoder, null))
-				.collect(Collectors.toList());
-		return new ResponseBodyResultHandler(converters, new DefaultConversionService(), resolver);
-	}
-
-	private ServerWebExchange createExchange(String path) throws URISyntaxException {
-		ServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, new URI(path));
-		WebSessionManager sessionManager = mock(WebSessionManager.class);
-		return new DefaultServerWebExchange(request, new MockServerHttpResponse(), sessionManager);
 	}
 
 
-	@SuppressWarnings("unused")
+	@RestController @SuppressWarnings("unused")
+	private static class TestRestController {
+
+		public String handleReturningString() {
+			return null;
+		}
+
+		public Void handleReturningVoid() {
+			return null;
+		}
+	}
+
+	@Controller @SuppressWarnings("unused")
 	private static class TestController {
 
-		public Publisher<String> notAnnotated() {
+		@ResponseBody
+		public String handleReturningString() {
 			return null;
 		}
 
 		@ResponseBody
-		public Publisher<String> publisherString() {
+		public Void handleReturningVoid() {
 			return null;
 		}
 
-		@ResponseBody
+		public String doWork() {
-		public Publisher<Void> publisherVoid() {
 			return null;
 		}
+
 	}
 
 }

spring-web-reactive/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandlerTests.java

@@ -16,134 +16,139 @@
 package org.springframework.web.reactive.result.method.annotation;
 
 import java.net.URI;
-import java.net.URISyntaxException;
+import java.time.Duration;
-import java.nio.charset.Charset;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import java.util.stream.Collectors;
 
+import org.junit.Before;
 import org.junit.Test;
-import reactor.core.test.TestSubscriber;
 
 import org.springframework.core.ResolvableType;
-import org.springframework.core.codec.Encoder;
+import org.springframework.core.codec.support.ByteBufferEncoder;
 import org.springframework.core.codec.support.JacksonJsonEncoder;
+import org.springframework.core.codec.support.Jaxb2Encoder;
 import org.springframework.core.codec.support.StringEncoder;
 import org.springframework.core.convert.support.DefaultConversionService;
-import org.springframework.core.io.buffer.support.DataBufferTestUtils;
+import org.springframework.core.convert.support.GenericConversionService;
+import org.springframework.core.convert.support.ReactiveStreamsToCompletableFutureConverter;
+import org.springframework.core.convert.support.ReactiveStreamsToRxJava1Converter;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.converter.reactive.CodecHttpMessageConverter;
 import org.springframework.http.converter.reactive.HttpMessageConverter;
+import org.springframework.http.converter.reactive.ResourceHttpMessageConverter;
 import org.springframework.http.server.reactive.MockServerHttpRequest;
 import org.springframework.http.server.reactive.MockServerHttpResponse;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.ui.ExtendedModelMap;
-import org.springframework.web.method.HandlerMethod;
+import org.springframework.ui.ModelMap;
+import org.springframework.util.ObjectUtils;
 import org.springframework.web.reactive.HandlerResult;
-import org.springframework.web.reactive.HandlerResultHandler;
-import org.springframework.web.reactive.accept.FixedContentTypeResolver;
-import org.springframework.web.reactive.accept.HeaderContentTypeResolver;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.adapter.DefaultServerWebExchange;
 import org.springframework.web.server.session.WebSessionManager;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
-import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8;
 
 /**
- * Unit tests for {@link ResponseEntityResultHandler}.
+ * Unit tests for {@link ResponseEntityResultHandler}. When adding a test also
+ * consider whether the logic under test is in a parent class, then see:
+ * <ul>
+ * 	<li>{@code MessageConverterResultHandlerTests},
+ *  <li>{@code ContentNegotiatingResultHandlerSupportTests}
+ * </ul>
  * @author Rossen Stoyanchev
  */
 public class ResponseEntityResultHandlerTests {
 
+	private static final Object HANDLER = new Object();
+
+
+	private ResponseEntityResultHandler resultHandler;
+
 	private MockServerHttpResponse response = new MockServerHttpResponse();
 
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.resultHandler = createHandler();
+		ServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, new URI("/path"));
+		this.exchange = new DefaultServerWebExchange(request, this.response, mock(WebSessionManager.class));
+	}
+
+	private ResponseEntityResultHandler createHandler(HttpMessageConverter<?>... converters) {
+		List<HttpMessageConverter<?>> converterList;
+		if (ObjectUtils.isEmpty(converters)) {
+			converterList = new ArrayList<>();
+			converterList.add(new CodecHttpMessageConverter<>(new ByteBufferEncoder()));
+			converterList.add(new CodecHttpMessageConverter<>(new StringEncoder()));
+			converterList.add(new ResourceHttpMessageConverter());
+			converterList.add(new CodecHttpMessageConverter<>(new Jaxb2Encoder()));
+			converterList.add(new CodecHttpMessageConverter<>(new JacksonJsonEncoder()));
+		}
+		else {
+			converterList = Arrays.asList(converters);
+		}
+		GenericConversionService service = new GenericConversionService();
+		service.addConverter(new ReactiveStreamsToCompletableFutureConverter());
+		service.addConverter(new ReactiveStreamsToRxJava1Converter());
+		RequestedContentTypeResolver resolver = new RequestedContentTypeResolverBuilder().build();
+
+		return new ResponseEntityResultHandler(converterList, new DefaultConversionService(), resolver);
+	}
+
 
 	@Test
 	public void supports() throws NoSuchMethodException {
-		ResponseEntityResultHandler handler = createHandler(new StringEncoder());
+		ModelMap model = new ExtendedModelMap();
-		TestController controller = new TestController();
 
-		HandlerMethod hm = new HandlerMethod(controller, TestController.class.getMethod("responseString"));
+		ResolvableType type = ResolvableType.forClassWithGenerics(ResponseEntity.class, String.class);
-		ResolvableType type = ResolvableType.forMethodParameter(hm.getReturnType());
+		assertTrue(this.resultHandler.supports(new HandlerResult(HANDLER, null, type, model)));
-		assertTrue(handler.supports(new HandlerResult(hm, null, type, new ExtendedModelMap())));
 
-		hm = new HandlerMethod(controller, TestController.class.getMethod("responseVoid"));
+		type = ResolvableType.forClassWithGenerics(ResponseEntity.class, Void.class);
-		type = ResolvableType.forMethodParameter(hm.getReturnType());
+		assertTrue(this.resultHandler.supports(new HandlerResult(HANDLER, null, type, model)));
-		assertTrue(handler.supports(new HandlerResult(hm, null, type, new ExtendedModelMap())));
 
-		hm = new HandlerMethod(controller, TestController.class.getMethod("string"));
+		type = ResolvableType.forClass(Void.class);
-		type = ResolvableType.forMethodParameter(hm.getReturnType());
+		assertFalse(this.resultHandler.supports(new HandlerResult(HANDLER, null, type, model)));
-		assertFalse(handler.supports(new HandlerResult(hm, null, type, new ExtendedModelMap())));
 	}
 
 	@Test
 	public void defaultOrder() throws Exception {
-		ResponseEntityResultHandler handler = createHandler(new StringEncoder());
+		assertEquals(0, this.resultHandler.getOrder());
-		assertEquals(0, handler.getOrder());
 	}
 
 	@Test
-	public void jsonResponseBody() throws Exception {
+	public void statusCode() throws Exception {
-		RequestedContentTypeResolver resolver = new FixedContentTypeResolver(APPLICATION_JSON_UTF8);
+		ResolvableType type = ResolvableType.forClassWithGenerics(ResponseEntity.class, Void.class);
-		HandlerResultHandler handler = createHandler(resolver, new StringEncoder(), new JacksonJsonEncoder());
+		HandlerResult result = new HandlerResult(HANDLER, ResponseEntity.noContent().build(), type);
+		this.resultHandler.handleResult(exchange, result).block(Duration.ofSeconds(5));
 
-		TestController controller = new TestController();
+		assertEquals(HttpStatus.NO_CONTENT, this.response.getStatus());
-		HandlerMethod hm = new HandlerMethod(controller, controller.getClass().getMethod("responseString"));
+		assertEquals(0, this.response.getHeaders().size());
-		ResolvableType type = ResolvableType.forMethodParameter(hm.getReturnType());
+		assertNull(this.response.getBody());
-		HandlerResult result = new HandlerResult(hm, ResponseEntity.ok("fooValue"), type);
-
-		ServerWebExchange exchange = createExchange("/foo");
-		handler.handleResult(exchange, result).block();
-
-		assertEquals(HttpStatus.OK, this.response.getStatus());
-		assertEquals(APPLICATION_JSON_UTF8, this.response.getHeaders().getContentType());
-		TestSubscriber.subscribe(this.response.getBody())
-				.assertValuesWith(buf -> assertEquals("\"fooValue\"",
-						DataBufferTestUtils.dumpString(buf, Charset.forName("UTF-8"))));
 	}
 
+	@Test
+	public void headers() throws Exception {
+		URI location = new URI("/path");
+		ResolvableType type = ResolvableType.forClassWithGenerics(ResponseEntity.class, Void.class);
+		HandlerResult result = new HandlerResult(HANDLER, ResponseEntity.created(location).build(), type);
+		this.resultHandler.handleResult(exchange, result).block(Duration.ofSeconds(5));
 
-	private ResponseEntityResultHandler createHandler(Encoder<?>... encoders) {
+		assertEquals(HttpStatus.CREATED, this.response.getStatus());
-		return createHandler(new HeaderContentTypeResolver(), encoders);
+		assertEquals(1, this.response.getHeaders().size());
-	}
+		assertEquals(location, this.response.getHeaders().getLocation());
-
+		assertNull(this.response.getBody());
-	private ResponseEntityResultHandler createHandler(RequestedContentTypeResolver resolver,
-			Encoder<?>... encoders) {
-
-		List<HttpMessageConverter<?>> converters = Arrays.stream(encoders)
-				.map(encoder -> new CodecHttpMessageConverter<>(encoder, null))
-				.collect(Collectors.toList());
-		return new ResponseEntityResultHandler(converters, new DefaultConversionService(), resolver);
-	}
-
-	private ServerWebExchange createExchange(String path) throws URISyntaxException {
-		ServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, new URI(path));
-		WebSessionManager sessionManager = mock(WebSessionManager.class);
-		return new DefaultServerWebExchange(request, this.response, sessionManager);
-	}
-
-
-	@SuppressWarnings("unused")
-	private static class TestController {
-
-		public ResponseEntity<String> responseString() {
-			return null;
-		}
-
-		public ResponseEntity<Void> responseVoid() {
-			return null;
-		}
-
-		public String string() {
-			return null;
-		}
 	}
 
 }