Introduce soft assertions for MockMvc

It happens very often that MockMvc is used in heavyweight integration
tests. It's no use to waste time to check if another condition has been
fixed or not. Soft assertions help a lot by checking all conditions at
once even if one of them fails.

See gh-26917

Co-authored-by: Sach Nguyen <sachnbbkhn@gmail.com>

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

@@ -42,7 +42,7 @@ public interface ResultActions {
 	 *   .andExpect(jsonPath("$.person.name").value("Jason"));
 	 * </pre>
 	 *
-	 * <p>Or alternatively provide all matchers as a vararg:
+	 * <p>Either provide all matchers as a vararg:
 	 * <pre class="code">
 	 * static imports: MockMvcRequestBuilders.*, MockMvcResultMatchers.*, ResultMatcher.matchAll
 	 *
@@ -56,6 +56,16 @@ public interface ResultActions {
 	 *       flash().attribute("message", "success!"))
 	 *   );
 	 * </pre>
+	 *
+	 * <p>Or provide all matchers to be evaluated no matter if one of them fail:
+	 * <pre class="code">
+	 * static imports: MockMvcRequestBuilders.*, MockMvcResultMatchers.*, ResultMatcher.matchAllSoftly
+	 * mockMvc.perform(post("/form"))
+	 *   .andExpect(matchAllSoftly(
+	 *       status().isOk(),
+	 *       redirectedUrl("/person/1")
+	 *   );
+	 * </pre>
 	 */
 	ResultActions andExpect(ResultMatcher matcher) throws Exception;
 

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

@@ -16,6 +16,9 @@
 
 package org.springframework.test.web.servlet;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * A {@code ResultMatcher} matches the result of an executed request against
  * some expectation.
@@ -70,4 +73,30 @@ public interface ResultMatcher {
 		};
 	}
 
+	/**
+	 * Static method for matching with an array of result matchers whose assertion failures are caught and stored.
+	 * Only when all of them would be called a {@link AssertionError} be thrown containing the error messages of those
+	 * previously caught assertion failures.
+	 * @param matchers the matchers
+	 * @author Michał Rowicki
+	 * @since 5.2
+	 */
+	static ResultMatcher matchAllSoftly(ResultMatcher... matchers) {
+		return result -> {
+			List<String> failedMessages = new ArrayList<>();
+			for (int i = 0; i < matchers.length; i++) {
+				ResultMatcher matcher = matchers[i];
+				try {
+					matcher.match(result);
+				}
+				catch (AssertionError assertionException) {
+					failedMessages.add("[" + i + "] " + assertionException.getMessage());
+				}
+			}
+			if (!failedMessages.isEmpty()) {
+				throw new AssertionError(String.join("\n", failedMessages));
+			}
+		};
+	}
+
 }

spring-test/src/test/java/org/springframework/test/web/servlet/ResultMatcherTests.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2002-2021 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.test.web.servlet;
+
+import org.jetbrains.annotations.NotNull;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatNoException;
+
+class ResultMatcherTests {
+
+	@Test
+	void whenProvidedMatcherPassesThenSoftAssertionsAlsoPasses() {
+		ResultMatcher resultMatcher = ResultMatcher.matchAllSoftly(this::doNothing);
+		StubMvcResult stubMvcResult = new StubMvcResult(null, null, null, null, null, null, null);
+
+		assertThatNoException().isThrownBy(() -> resultMatcher.match(stubMvcResult));
+	}
+
+	@Test
+	void whenOneOfMatcherFailsThenSoftAssertionFailsWithTheVerySameMessage() {
+		String failMessage = "fail message";
+		StubMvcResult stubMvcResult = new StubMvcResult(null, null, null, null, null, null, null);
+		ResultMatcher resultMatcher = ResultMatcher.matchAllSoftly(failMatcher(failMessage));
+
+		assertThatExceptionOfType(AssertionError.class)
+				.isThrownBy(() -> resultMatcher.match(stubMvcResult))
+				.withMessage("[0] " + failMessage);
+	}
+
+	@Test
+	void whenMultipleMatchersFailsThenSoftAssertionFailsWithOneErrorWithMessageContainingAllErrorMessagesWithTheSameOrder() {
+		String firstFail = "firstFail";
+		String secondFail = "secondFail";
+		StubMvcResult stubMvcResult = new StubMvcResult(null, null, null, null, null, null, null);
+		ResultMatcher resultMatcher = ResultMatcher.matchAllSoftly(failMatcher(firstFail), failMatcher(secondFail));
+
+		assertThatExceptionOfType(AssertionError.class)
+				.isThrownBy(() -> resultMatcher.match(stubMvcResult))
+				.withMessage("[0] " + firstFail + "\n[1] " + secondFail);
+	}
+
+	@NotNull
+	private ResultMatcher failMatcher(String failMessage) {
+		return result -> {
+			throw new AssertionError(failMessage);
+		};
+	}
+
+	void doNothing(MvcResult mvcResult) {}
+}