Polish soft assertion support for WebTestClient

See gh-26969

spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClient.java

@@ -21,7 +21,6 @@ import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.time.ZonedDateTime;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -45,6 +44,7 @@ import org.springframework.http.client.reactive.ClientHttpConnector;
 import org.springframework.http.client.reactive.ClientHttpRequest;
 import org.springframework.lang.Nullable;
 import org.springframework.test.util.AssertionErrors;
+import org.springframework.test.util.ExceptionCollector;
 import org.springframework.test.util.JsonExpectationsHelper;
 import org.springframework.test.util.XmlExpectationsHelper;
 import org.springframework.util.Assert;
@@ -64,6 +64,8 @@ import org.springframework.web.util.UriBuilderFactory;
  * Default implementation of {@link WebTestClient}.
  *
  * @author Rossen Stoyanchev
+ * @author Sam Brannen
+ * @author Michał Rowicki
  * @since 5.0
  */
 class DefaultWebTestClient implements WebTestClient {
@@ -510,19 +512,25 @@ class DefaultWebTestClient implements WebTestClient {
 		}
 
 		@Override
-		public ResponseSpec expectAllSoftly(ResponseSpecMatcher... asserts) {
-			List<String> failedMessages = new ArrayList<>();
-			for (int i = 0; i < asserts.length; i++) {
-				ResponseSpecMatcher anAssert = asserts[i];
-				try {
-					anAssert.accept(this);
-				}
-				catch (AssertionError assertionException) {
-					failedMessages.add("[" + i + "] " + assertionException.getMessage());
-				}
+		public ResponseSpec expectAll(ResponseSpecConsumer... consumers) {
+			ExceptionCollector exceptionCollector = new ExceptionCollector();
+			for (ResponseSpecConsumer consumer : consumers) {
+				exceptionCollector.execute(() -> consumer.accept(this));
 			}
-			if (!failedMessages.isEmpty()) {
-				throw new AssertionError(String.join("\n", failedMessages));
+			try {
+				exceptionCollector.assertEmpty();
+			}
+			catch (RuntimeException ex) {
+				throw ex;
+			}
+			catch (Exception ex) {
+				// In theory, a ResponseSpecConsumer should never throw an Exception
+				// that is not a RuntimeException, but since ExceptionCollector may
+				// throw a checked Exception, we handle this to appease the compiler
+				// and in case someone uses a "sneaky throws" technique.
+				AssertionError assertionError = new AssertionError(ex.getMessage());
+				assertionError.initCause(ex);
+				throw assertionError;
 			}
 			return this;
 		}

spring-test/src/main/java/org/springframework/test/web/reactive/server/WebTestClient.java

@@ -86,6 +86,8 @@ import org.springframework.web.util.UriBuilderFactory;
  *
  * @author Rossen Stoyanchev
  * @author Brian Clozel
+ * @author Sam Brannen
+ * @author Michał Rowicki
  * @since 5.0
  * @see StatusAssertions
  * @see HeaderAssertions
@@ -781,6 +783,34 @@ public interface WebTestClient {
 	 */
 	interface ResponseSpec {
 
+		/**
+		 * Apply multiple assertions to a response with the given
+		 * {@linkplain ResponseSpecConsumer consumers}, with the guarantee that
+		 * all assertions will be applied even if one or more assertions fails
+		 * with an exception.
+		 * <p>If a single {@link Error} or {@link RuntimeException} is thrown,
+		 * it will be rethrown.
+		 * <p>If multiple exceptions are thrown, this method will throw an
+		 * {@link AssertionError} whose error message is a summary of all of the
+		 * exceptions. In addition, each exception will be added as a
+		 * {@linkplain Throwable#addSuppressed(Throwable) suppressed exception} to
+		 * the {@code AssertionError}.
+		 * <p>This feature is similar to the {@code SoftAssertions} support in
+		 * AssertJ and the {@code assertAll()} support in JUnit Jupiter.
+		 *
+		 * <h4>Example</h4>
+		 * <pre class="code">
+		 * webTestClient.get().uri("/hello").exchange()
+		 *     .expectAll(
+		 *         responseSpec -> responseSpec.expectStatus().isOk(),
+		 *         responseSpec -> responseSpec.expectBody(String.class).isEqualTo("Hello, World!")
+		 *     );
+		 * </pre>
+		 * @param consumers the list of {@code ResponseSpec} consumers
+		 * @since 5.3.10
+		 */
+		ResponseSpec expectAll(ResponseSpecConsumer... consumers);
+
 		/**
 		 * Assertions on the response status.
 		 */
@@ -847,9 +877,14 @@ public interface WebTestClient {
 		<T> FluxExchangeResult<T> returnResult(ParameterizedTypeReference<T> elementTypeRef);
 
 		/**
-		 * Array of assertions to test together a.k.a. soft assertions.
+		 * {@link Consumer} of a {@link ResponseSpec}.
+		 * @since 5.3.10
+		 * @see ResponseSpec#expectAll(ResponseSpecConsumer...)
 		 */
-		ResponseSpec expectAllSoftly(ResponseSpecMatcher... asserts);
+		@FunctionalInterface
+		interface ResponseSpecConsumer extends Consumer<ResponseSpec> {
+		}
+
 	}
 
 
@@ -1011,5 +1046,4 @@ public interface WebTestClient {
 		EntityExchangeResult<byte[]> returnResult();
 	}
 
-	interface ResponseSpecMatcher extends Consumer<ResponseSpec> {}
 }