Add bufferContent option to MockRestServiceServer

Issue: SPR-14694

spring-test/src/main/java/org/springframework/test/web/client/MockRestServiceServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.net.URI;
 
 import org.springframework.http.HttpMethod;
+import org.springframework.http.client.BufferingClientHttpRequestFactory;
 import org.springframework.http.client.ClientHttpRequest;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.ClientHttpResponse;
@@ -201,6 +202,14 @@ public class MockRestServiceServer {
 		 */
 		MockRestServiceServerBuilder ignoreExpectOrder(boolean ignoreExpectOrder);
 
+		/**
+		 * Use the {@link BufferingClientHttpRequestFactory} wrapper to buffer
+		 * the input and output streams, and for example, allow multiple reads
+		 * of the response body.
+		 * @since 5.0.5
+		 */
+		MockRestServiceServerBuilder bufferContent();
+
 		/**
 		 * Build the {@code MockRestServiceServer} and set up the underlying
 		 * {@code RestTemplate} or {@code AsyncRestTemplate} with a
@@ -226,6 +235,9 @@ public class MockRestServiceServer {
 
 		private boolean ignoreExpectOrder;
 
+		private boolean bufferContent;
+
+
 		public DefaultBuilder(RestTemplate restTemplate) {
 			Assert.notNull(restTemplate, "RestTemplate must not be null");
 			this.restTemplate = restTemplate;
@@ -244,6 +256,12 @@ public class MockRestServiceServer {
 			return this;
 		}
 
+		@Override
+		public MockRestServiceServerBuilder bufferContent() {
+			this.bufferContent = true;
+			return this;
+		}
+
 		@Override
 		public MockRestServiceServer build() {
 			if (this.ignoreExpectOrder) {
@@ -259,8 +277,13 @@ public class MockRestServiceServer {
 			MockRestServiceServer server = new MockRestServiceServer(manager);
 			MockClientHttpRequestFactory factory = server.new MockClientHttpRequestFactory();
 			if (this.restTemplate != null) {
+				if (this.bufferContent) {
+					this.restTemplate.setRequestFactory(new BufferingClientHttpRequestFactory(factory));
+				}
+				else {
 					this.restTemplate.setRequestFactory(factory);
 				}
+			}
 			if (this.asyncRestTemplate != null) {
 				this.asyncRestTemplate.setAsyncRequestFactory(factory);
 			}

spring-test/src/test/java/org/springframework/test/web/client/samples/SampleTests.java

@@ -15,18 +15,26 @@
  */
 package org.springframework.test.web.client.samples;
 
+import java.io.IOException;
+import java.util.Collections;
+
 import org.junit.Before;
 import org.junit.Test;
 
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpRequest;
 import org.springframework.http.MediaType;
+import org.springframework.http.client.ClientHttpRequestExecution;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.test.web.Person;
 import org.springframework.test.web.client.MockRestServiceServer;
+import org.springframework.util.FileCopyUtils;
 import org.springframework.web.client.RestTemplate;
 
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 import static org.springframework.test.web.client.ExpectedCount.manyTimes;
 import static org.springframework.test.web.client.ExpectedCount.never;
 import static org.springframework.test.web.client.ExpectedCount.once;
@@ -55,7 +63,7 @@ public class SampleTests {
 	}
 
 	@Test
-	public void performGet() throws Exception {
+	public void performGet() {
 
 		String responseBody = "{\"name\" : \"Ludwig van Beethoven\", \"someDouble\" : \"1.6035\"}";
 
@@ -73,7 +81,7 @@ public class SampleTests {
 	}
 
 	@Test
-	public void performGetManyTimes() throws Exception {
+	public void performGetManyTimes() {
 
 		String responseBody = "{\"name\" : \"Ludwig van Beethoven\", \"someDouble\" : \"1.6035\"}";
 
@@ -95,7 +103,7 @@ public class SampleTests {
 	}
 
 	@Test
-	public void expectNever() throws Exception {
+	public void expectNever() {
 
 		String responseBody = "{\"name\" : \"Ludwig van Beethoven\", \"someDouble\" : \"1.6035\"}";
 
@@ -110,7 +118,7 @@ public class SampleTests {
 	}
 
 	@Test(expected = AssertionError.class)
-	public void expectNeverViolated() throws Exception {
+	public void expectNeverViolated() {
 
 		String responseBody = "{\"name\" : \"Ludwig van Beethoven\", \"someDouble\" : \"1.6035\"}";
 
@@ -124,7 +132,7 @@ public class SampleTests {
 	}
 
 	@Test
-	public void performGetWithResponseBodyFromFile() throws Exception {
+	public void performGetWithResponseBodyFromFile() {
 
 		Resource responseBody = new ClassPathResource("ludwig.json", this.getClass());
 
@@ -170,4 +178,48 @@ public class SampleTests {
 			assertTrue(error.getMessage(), error.getMessage().contains("2 unsatisfied expectation(s)"));
 		}
 	}
+
+	@Test // SPR-14694
+	public void repeatedAccessToResponseViaResource() {
+
+		Resource resource = new ClassPathResource("ludwig.json", this.getClass());
+
+		RestTemplate restTemplate = new RestTemplate();
+		restTemplate.setInterceptors(Collections.singletonList(new ContentInterceptor(resource)));
+
+		MockRestServiceServer mockServer = MockRestServiceServer.bindTo(restTemplate)
+				.ignoreExpectOrder(true)
+				.bufferContent()  // enable repeated reads of response body
+				.build();
+
+		mockServer.expect(requestTo("/composers/42")).andExpect(method(HttpMethod.GET))
+				.andRespond(withSuccess(resource, MediaType.APPLICATION_JSON));
+
+		restTemplate.getForObject("/composers/{id}", Person.class, 42);
+
+		mockServer.verify();
+	}
+
+
+	private static class ContentInterceptor implements ClientHttpRequestInterceptor {
+
+		private final Resource resource;
+
+
+		private ContentInterceptor(Resource resource) {
+			this.resource = resource;
+		}
+
+		@Override
+		public ClientHttpResponse intercept(HttpRequest request, byte[] body,
+				ClientHttpRequestExecution execution) throws IOException {
+
+			ClientHttpResponse response = execution.execute(request, body);
+			byte[] expected = FileCopyUtils.copyToByteArray(this.resource.getInputStream());
+			byte[] actual = FileCopyUtils.copyToByteArray(response.getBody());
+			assertEquals(new String(expected), new String(actual));
+			return response;
+		}
+	}
+
 }