From be807bab12a6b20033bd5494d63899399a3fdc13 Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <wilkinsona@vmware.com>
Date: Mon, 17 May 2021 11:07:23 +0100
Subject: [PATCH] Polish "Improve documentation of TestRestTemplate's fault
 tolerance"

See gh-26227
---
 .../docs/asciidoc/spring-boot-features.adoc   |   4 +-
 .../test/web/client/TestRestTemplate.java     | 105 ++++++++----------
 2 files changed, 52 insertions(+), 57 deletions(-)

diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc
index 6277ce8d65..642773ffaa 100644
--- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc
+++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc
@@ -7606,7 +7606,9 @@ include::{test-examples}/test/system/OutputCaptureTests.java[tag=test]
 ==== TestRestTemplate
 `TestRestTemplate` is a convenience alternative to Spring's `RestTemplate` that is useful in integration tests.
 You can get a vanilla template or one that sends Basic HTTP authentication (with a username and password).
-In either case, the template behaves in a test-friendly way by not throwing exceptions on server-side errors.
+In either case, the template is fault tolerant.
+This means that it behaves in a test-friendly way by not throwing exceptions on 4xx and 5xx errors.
+Instead, such errors can be detected via the returned `ResponseEntity` and its status code.
 
 TIP: Spring Framework 5.0 provides a new `WebTestClient` that works for <<boot-features-testing-spring-boot-applications-testing-autoconfigured-webflux-tests, WebFlux integration tests>> and both <<boot-features-testing-spring-boot-applications-testing-with-running-server, WebFlux and MVC end-to-end testing>>.
 It provides a fluent API for assertions, unlike `TestRestTemplate`.
diff --git a/spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java b/spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java
index 4f4380d097..56dcf3a96f 100644
--- a/spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java
+++ b/spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -49,16 +49,19 @@ import org.springframework.util.Assert;
 import org.springframework.web.client.DefaultResponseErrorHandler;
 import org.springframework.web.client.RequestCallback;
 import org.springframework.web.client.ResponseExtractor;
-import org.springframework.web.client.RestClientException;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.util.DefaultUriBuilderFactory;
 import org.springframework.web.util.UriTemplateHandler;
 
 /**
  * Convenient alternative of {@link RestTemplate} that is suitable for integration tests.
- * They are fault tolerant, and optionally can carry Basic authentication headers. If
- * Apache Http Client 4.3.2 or better is available (recommended) it will be used as the
- * client, and by default configured to ignore cookies and redirects.
+ * {@code TestRestTemplate} is fault tolerant. This means that 4xx and 5xx do not result
+ * in an exception being thrown and can instead be detected via the {@link ResponseEntity
+ * response entity} and its {@link ResponseEntity#getStatusCode() status code}.
+ * <p>
+ * A {@code TestRestTemplate} can optionally carry Basic authentication headers. If Apache
+ * Http Client 4.3.2 or better is available (recommended) it will be used as the client,
+ * and by default configured to ignore cookies and redirects.
  * <p>
  * Note: To prevent injection problems this class intentionally does not extend
  * {@link RestTemplate}. If you need access to the underlying {@link RestTemplate} use
@@ -177,7 +180,7 @@ public class TestRestTemplate {
 	 * @return the converted object
 	 * @see RestTemplate#getForObject(String, Class, Object...)
 	 */
-	public <T> T getForObject(String url, Class<T> responseType, Object... urlVariables) throws RestClientException {
+	public <T> T getForObject(String url, Class<T> responseType, Object... urlVariables) {
 		return this.restTemplate.getForObject(url, responseType, urlVariables);
 	}
 
@@ -193,8 +196,7 @@ public class TestRestTemplate {
 	 * @return the converted object
 	 * @see RestTemplate#getForObject(String, Class, Object...)
 	 */
-	public <T> T getForObject(String url, Class<T> responseType, Map<String, ?> urlVariables)
-			throws RestClientException {
+	public <T> T getForObject(String url, Class<T> responseType, Map<String, ?> urlVariables) {
 		return this.restTemplate.getForObject(url, responseType, urlVariables);
 	}
 
@@ -207,7 +209,7 @@ public class TestRestTemplate {
 	 * @return the converted object
 	 * @see RestTemplate#getForObject(java.net.URI, java.lang.Class)
 	 */
-	public <T> T getForObject(URI url, Class<T> responseType) throws RestClientException {
+	public <T> T getForObject(URI url, Class<T> responseType) {
 		return this.restTemplate.getForObject(applyRootUriIfNecessary(url), responseType);
 	}
 
@@ -224,8 +226,7 @@ public class TestRestTemplate {
 	 * @see RestTemplate#getForEntity(java.lang.String, java.lang.Class,
 	 * java.lang.Object[])
 	 */
-	public <T> ResponseEntity<T> getForEntity(String url, Class<T> responseType, Object... urlVariables)
-			throws RestClientException {
+	public <T> ResponseEntity<T> getForEntity(String url, Class<T> responseType, Object... urlVariables) {
 		return this.restTemplate.getForEntity(url, responseType, urlVariables);
 	}
 
@@ -241,8 +242,7 @@ public class TestRestTemplate {
 	 * @return the converted object
 	 * @see RestTemplate#getForEntity(java.lang.String, java.lang.Class, java.util.Map)
 	 */
-	public <T> ResponseEntity<T> getForEntity(String url, Class<T> responseType, Map<String, ?> urlVariables)
-			throws RestClientException {
+	public <T> ResponseEntity<T> getForEntity(String url, Class<T> responseType, Map<String, ?> urlVariables) {
 		return this.restTemplate.getForEntity(url, responseType, urlVariables);
 	}
 
@@ -255,7 +255,7 @@ public class TestRestTemplate {
 	 * @return the converted object
 	 * @see RestTemplate#getForEntity(java.net.URI, java.lang.Class)
 	 */
-	public <T> ResponseEntity<T> getForEntity(URI url, Class<T> responseType) throws RestClientException {
+	public <T> ResponseEntity<T> getForEntity(URI url, Class<T> responseType) {
 		return this.restTemplate.getForEntity(applyRootUriIfNecessary(url), responseType);
 	}
 
@@ -268,7 +268,7 @@ public class TestRestTemplate {
 	 * @return all HTTP headers of that resource
 	 * @see RestTemplate#headForHeaders(java.lang.String, java.lang.Object[])
 	 */
-	public HttpHeaders headForHeaders(String url, Object... urlVariables) throws RestClientException {
+	public HttpHeaders headForHeaders(String url, Object... urlVariables) {
 		return this.restTemplate.headForHeaders(url, urlVariables);
 	}
 
@@ -281,7 +281,7 @@ public class TestRestTemplate {
 	 * @return all HTTP headers of that resource
 	 * @see RestTemplate#headForHeaders(java.lang.String, java.util.Map)
 	 */
-	public HttpHeaders headForHeaders(String url, Map<String, ?> urlVariables) throws RestClientException {
+	public HttpHeaders headForHeaders(String url, Map<String, ?> urlVariables) {
 		return this.restTemplate.headForHeaders(url, urlVariables);
 	}
 
@@ -291,7 +291,7 @@ public class TestRestTemplate {
 	 * @return all HTTP headers of that resource
 	 * @see RestTemplate#headForHeaders(java.net.URI)
 	 */
-	public HttpHeaders headForHeaders(URI url) throws RestClientException {
+	public HttpHeaders headForHeaders(URI url) {
 		return this.restTemplate.headForHeaders(applyRootUriIfNecessary(url));
 	}
 
@@ -312,7 +312,7 @@ public class TestRestTemplate {
 	 * @see RestTemplate#postForLocation(java.lang.String, java.lang.Object,
 	 * java.lang.Object[])
 	 */
-	public URI postForLocation(String url, Object request, Object... urlVariables) throws RestClientException {
+	public URI postForLocation(String url, Object request, Object... urlVariables) {
 		return this.restTemplate.postForLocation(url, request, urlVariables);
 	}
 
@@ -333,7 +333,7 @@ public class TestRestTemplate {
 	 * @see RestTemplate#postForLocation(java.lang.String, java.lang.Object,
 	 * java.util.Map)
 	 */
-	public URI postForLocation(String url, Object request, Map<String, ?> urlVariables) throws RestClientException {
+	public URI postForLocation(String url, Object request, Map<String, ?> urlVariables) {
 		return this.restTemplate.postForLocation(url, request, urlVariables);
 	}
 
@@ -350,7 +350,7 @@ public class TestRestTemplate {
 	 * @see HttpEntity
 	 * @see RestTemplate#postForLocation(java.net.URI, java.lang.Object)
 	 */
-	public URI postForLocation(URI url, Object request) throws RestClientException {
+	public URI postForLocation(URI url, Object request) {
 		return this.restTemplate.postForLocation(applyRootUriIfNecessary(url), request);
 	}
 
@@ -372,8 +372,7 @@ public class TestRestTemplate {
 	 * @see RestTemplate#postForObject(java.lang.String, java.lang.Object,
 	 * java.lang.Class, java.lang.Object[])
 	 */
-	public <T> T postForObject(String url, Object request, Class<T> responseType, Object... urlVariables)
-			throws RestClientException {
+	public <T> T postForObject(String url, Object request, Class<T> responseType, Object... urlVariables) {
 		return this.restTemplate.postForObject(url, request, responseType, urlVariables);
 	}
 
@@ -395,8 +394,7 @@ public class TestRestTemplate {
 	 * @see RestTemplate#postForObject(java.lang.String, java.lang.Object,
 	 * java.lang.Class, java.util.Map)
 	 */
-	public <T> T postForObject(String url, Object request, Class<T> responseType, Map<String, ?> urlVariables)
-			throws RestClientException {
+	public <T> T postForObject(String url, Object request, Class<T> responseType, Map<String, ?> urlVariables) {
 		return this.restTemplate.postForObject(url, request, responseType, urlVariables);
 	}
 
@@ -414,7 +412,7 @@ public class TestRestTemplate {
 	 * @see HttpEntity
 	 * @see RestTemplate#postForObject(java.net.URI, java.lang.Object, java.lang.Class)
 	 */
-	public <T> T postForObject(URI url, Object request, Class<T> responseType) throws RestClientException {
+	public <T> T postForObject(URI url, Object request, Class<T> responseType) {
 		return this.restTemplate.postForObject(applyRootUriIfNecessary(url), request, responseType);
 	}
 
@@ -437,7 +435,7 @@ public class TestRestTemplate {
 	 * java.lang.Class, java.lang.Object[])
 	 */
 	public <T> ResponseEntity<T> postForEntity(String url, Object request, Class<T> responseType,
-			Object... urlVariables) throws RestClientException {
+			Object... urlVariables) {
 		return this.restTemplate.postForEntity(url, request, responseType, urlVariables);
 	}
 
@@ -460,7 +458,7 @@ public class TestRestTemplate {
 	 * java.lang.Class, java.util.Map)
 	 */
 	public <T> ResponseEntity<T> postForEntity(String url, Object request, Class<T> responseType,
-			Map<String, ?> urlVariables) throws RestClientException {
+			Map<String, ?> urlVariables) {
 		return this.restTemplate.postForEntity(url, request, responseType, urlVariables);
 	}
 
@@ -478,8 +476,7 @@ public class TestRestTemplate {
 	 * @see HttpEntity
 	 * @see RestTemplate#postForEntity(java.net.URI, java.lang.Object, java.lang.Class)
 	 */
-	public <T> ResponseEntity<T> postForEntity(URI url, Object request, Class<T> responseType)
-			throws RestClientException {
+	public <T> ResponseEntity<T> postForEntity(URI url, Object request, Class<T> responseType) {
 		return this.restTemplate.postForEntity(applyRootUriIfNecessary(url), request, responseType);
 	}
 
@@ -499,7 +496,7 @@ public class TestRestTemplate {
 	 * @see HttpEntity
 	 * @see RestTemplate#put(java.lang.String, java.lang.Object, java.lang.Object[])
 	 */
-	public void put(String url, Object request, Object... urlVariables) throws RestClientException {
+	public void put(String url, Object request, Object... urlVariables) {
 		this.restTemplate.put(url, request, urlVariables);
 	}
 
@@ -519,7 +516,7 @@ public class TestRestTemplate {
 	 * @see HttpEntity
 	 * @see RestTemplate#put(java.lang.String, java.lang.Object, java.util.Map)
 	 */
-	public void put(String url, Object request, Map<String, ?> urlVariables) throws RestClientException {
+	public void put(String url, Object request, Map<String, ?> urlVariables) {
 		this.restTemplate.put(url, request, urlVariables);
 	}
 
@@ -536,7 +533,7 @@ public class TestRestTemplate {
 	 * @see HttpEntity
 	 * @see RestTemplate#put(java.net.URI, java.lang.Object)
 	 */
-	public void put(URI url, Object request) throws RestClientException {
+	public void put(URI url, Object request) {
 		this.restTemplate.put(applyRootUriIfNecessary(url), request);
 	}
 
@@ -557,8 +554,7 @@ public class TestRestTemplate {
 	 * @since 1.4.4
 	 * @see HttpEntity
 	 */
-	public <T> T patchForObject(String url, Object request, Class<T> responseType, Object... uriVariables)
-			throws RestClientException {
+	public <T> T patchForObject(String url, Object request, Class<T> responseType, Object... uriVariables) {
 		return this.restTemplate.patchForObject(url, request, responseType, uriVariables);
 	}
 
@@ -579,8 +575,7 @@ public class TestRestTemplate {
 	 * @since 1.4.4
 	 * @see HttpEntity
 	 */
-	public <T> T patchForObject(String url, Object request, Class<T> responseType, Map<String, ?> uriVariables)
-			throws RestClientException {
+	public <T> T patchForObject(String url, Object request, Class<T> responseType, Map<String, ?> uriVariables) {
 		return this.restTemplate.patchForObject(url, request, responseType, uriVariables);
 	}
 
@@ -598,7 +593,7 @@ public class TestRestTemplate {
 	 * @since 1.4.4
 	 * @see HttpEntity
 	 */
-	public <T> T patchForObject(URI url, Object request, Class<T> responseType) throws RestClientException {
+	public <T> T patchForObject(URI url, Object request, Class<T> responseType) {
 		return this.restTemplate.patchForObject(applyRootUriIfNecessary(url), request, responseType);
 	}
 
@@ -613,7 +608,7 @@ public class TestRestTemplate {
 	 * @param urlVariables the variables to expand in the template
 	 * @see RestTemplate#delete(java.lang.String, java.lang.Object[])
 	 */
-	public void delete(String url, Object... urlVariables) throws RestClientException {
+	public void delete(String url, Object... urlVariables) {
 		this.restTemplate.delete(url, urlVariables);
 	}
 
@@ -628,7 +623,7 @@ public class TestRestTemplate {
 	 * @param urlVariables the variables to expand the template
 	 * @see RestTemplate#delete(java.lang.String, java.util.Map)
 	 */
-	public void delete(String url, Map<String, ?> urlVariables) throws RestClientException {
+	public void delete(String url, Map<String, ?> urlVariables) {
 		this.restTemplate.delete(url, urlVariables);
 	}
 
@@ -640,7 +635,7 @@ public class TestRestTemplate {
 	 * @param url the URL
 	 * @see RestTemplate#delete(java.net.URI)
 	 */
-	public void delete(URI url) throws RestClientException {
+	public void delete(URI url) {
 		this.restTemplate.delete(applyRootUriIfNecessary(url));
 	}
 
@@ -653,7 +648,7 @@ public class TestRestTemplate {
 	 * @return the value of the allow header
 	 * @see RestTemplate#optionsForAllow(java.lang.String, java.lang.Object[])
 	 */
-	public Set<HttpMethod> optionsForAllow(String url, Object... urlVariables) throws RestClientException {
+	public Set<HttpMethod> optionsForAllow(String url, Object... urlVariables) {
 		return this.restTemplate.optionsForAllow(url, urlVariables);
 	}
 
@@ -666,7 +661,7 @@ public class TestRestTemplate {
 	 * @return the value of the allow header
 	 * @see RestTemplate#optionsForAllow(java.lang.String, java.util.Map)
 	 */
-	public Set<HttpMethod> optionsForAllow(String url, Map<String, ?> urlVariables) throws RestClientException {
+	public Set<HttpMethod> optionsForAllow(String url, Map<String, ?> urlVariables) {
 		return this.restTemplate.optionsForAllow(url, urlVariables);
 	}
 
@@ -676,7 +671,7 @@ public class TestRestTemplate {
 	 * @return the value of the allow header
 	 * @see RestTemplate#optionsForAllow(java.net.URI)
 	 */
-	public Set<HttpMethod> optionsForAllow(URI url) throws RestClientException {
+	public Set<HttpMethod> optionsForAllow(URI url) {
 		return this.restTemplate.optionsForAllow(applyRootUriIfNecessary(url));
 	}
 
@@ -697,7 +692,7 @@ public class TestRestTemplate {
 	 * org.springframework.http.HttpEntity, java.lang.Class, java.lang.Object[])
 	 */
 	public <T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity,
-			Class<T> responseType, Object... urlVariables) throws RestClientException {
+			Class<T> responseType, Object... urlVariables) {
 		return this.restTemplate.exchange(url, method, requestEntity, responseType, urlVariables);
 	}
 
@@ -718,7 +713,7 @@ public class TestRestTemplate {
 	 * org.springframework.http.HttpEntity, java.lang.Class, java.util.Map)
 	 */
 	public <T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity,
-			Class<T> responseType, Map<String, ?> urlVariables) throws RestClientException {
+			Class<T> responseType, Map<String, ?> urlVariables) {
 		return this.restTemplate.exchange(url, method, requestEntity, responseType, urlVariables);
 	}
 
@@ -736,7 +731,7 @@ public class TestRestTemplate {
 	 * org.springframework.http.HttpEntity, java.lang.Class)
 	 */
 	public <T> ResponseEntity<T> exchange(URI url, HttpMethod method, HttpEntity<?> requestEntity,
-			Class<T> responseType) throws RestClientException {
+			Class<T> responseType) {
 		return this.restTemplate.exchange(applyRootUriIfNecessary(url), method, requestEntity, responseType);
 	}
 
@@ -761,7 +756,7 @@ public class TestRestTemplate {
 	 * org.springframework.core.ParameterizedTypeReference, java.lang.Object[])
 	 */
 	public <T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity,
-			ParameterizedTypeReference<T> responseType, Object... urlVariables) throws RestClientException {
+			ParameterizedTypeReference<T> responseType, Object... urlVariables) {
 		return this.restTemplate.exchange(url, method, requestEntity, responseType, urlVariables);
 	}
 
@@ -786,7 +781,7 @@ public class TestRestTemplate {
 	 * org.springframework.core.ParameterizedTypeReference, java.util.Map)
 	 */
 	public <T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity,
-			ParameterizedTypeReference<T> responseType, Map<String, ?> urlVariables) throws RestClientException {
+			ParameterizedTypeReference<T> responseType, Map<String, ?> urlVariables) {
 		return this.restTemplate.exchange(url, method, requestEntity, responseType, urlVariables);
 	}
 
@@ -810,7 +805,7 @@ public class TestRestTemplate {
 	 * org.springframework.core.ParameterizedTypeReference)
 	 */
 	public <T> ResponseEntity<T> exchange(URI url, HttpMethod method, HttpEntity<?> requestEntity,
-			ParameterizedTypeReference<T> responseType) throws RestClientException {
+			ParameterizedTypeReference<T> responseType) {
 		return this.restTemplate.exchange(applyRootUriIfNecessary(url), method, requestEntity, responseType);
 	}
 
@@ -828,8 +823,7 @@ public class TestRestTemplate {
 	 * @return the response as entity
 	 * @see RestTemplate#exchange(org.springframework.http.RequestEntity, java.lang.Class)
 	 */
-	public <T> ResponseEntity<T> exchange(RequestEntity<?> requestEntity, Class<T> responseType)
-			throws RestClientException {
+	public <T> ResponseEntity<T> exchange(RequestEntity<?> requestEntity, Class<T> responseType) {
 		return this.restTemplate.exchange(createRequestEntityWithRootAppliedUri(requestEntity), responseType);
 	}
 
@@ -849,8 +843,7 @@ public class TestRestTemplate {
 	 * @see RestTemplate#exchange(org.springframework.http.RequestEntity,
 	 * org.springframework.core.ParameterizedTypeReference)
 	 */
-	public <T> ResponseEntity<T> exchange(RequestEntity<?> requestEntity, ParameterizedTypeReference<T> responseType)
-			throws RestClientException {
+	public <T> ResponseEntity<T> exchange(RequestEntity<?> requestEntity, ParameterizedTypeReference<T> responseType) {
 		return this.restTemplate.exchange(createRequestEntityWithRootAppliedUri(requestEntity), responseType);
 	}
 
@@ -871,7 +864,7 @@ public class TestRestTemplate {
 	 * org.springframework.web.client.ResponseExtractor, java.lang.Object[])
 	 */
 	public <T> T execute(String url, HttpMethod method, RequestCallback requestCallback,
-			ResponseExtractor<T> responseExtractor, Object... urlVariables) throws RestClientException {
+			ResponseExtractor<T> responseExtractor, Object... urlVariables) {
 		return this.restTemplate.execute(url, method, requestCallback, responseExtractor, urlVariables);
 	}
 
@@ -892,7 +885,7 @@ public class TestRestTemplate {
 	 * org.springframework.web.client.ResponseExtractor, java.util.Map)
 	 */
 	public <T> T execute(String url, HttpMethod method, RequestCallback requestCallback,
-			ResponseExtractor<T> responseExtractor, Map<String, ?> urlVariables) throws RestClientException {
+			ResponseExtractor<T> responseExtractor, Map<String, ?> urlVariables) {
 		return this.restTemplate.execute(url, method, requestCallback, responseExtractor, urlVariables);
 	}
 
@@ -910,7 +903,7 @@ public class TestRestTemplate {
 	 * org.springframework.web.client.ResponseExtractor)
 	 */
 	public <T> T execute(URI url, HttpMethod method, RequestCallback requestCallback,
-			ResponseExtractor<T> responseExtractor) throws RestClientException {
+			ResponseExtractor<T> responseExtractor) {
 		return this.restTemplate.execute(applyRootUriIfNecessary(url), method, requestCallback, responseExtractor);
 	}