Polish soft assertion support for WebTestClient

See spring-projectsgh-26969

Author: sbrannen

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

@@ -21,7 +21,6 @@
 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.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 @@
  * 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 @@ public <T> FluxExchangeResult<T> returnResult(ParameterizedTypeReference<T> elem
 		}
 
 		@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));
+			}
+			try {
+				exceptionCollector.assertEmpty();
+			}
+			catch (RuntimeException ex) {
+				throw ex;
 			}
-			if (!failedMessages.isEmpty()) {
-				throw new AssertionError(String.join("\n", failedMessages));
+			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 @@
  *
  * @author Rossen Stoyanchev
  * @author Brian Clozel
+ * @author Sam Brannen
+ * @author Michał Rowicki
  * @since 5.0
  * @see StatusAssertions
  * @see HeaderAssertions
@@ -781,6 +783,34 @@ interface RequestBodyUriSpec extends RequestBodySpec, RequestHeadersUriSpec<Requ
 	 */
 	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 @@ interface ResponseSpec {
 		<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 @@ default XpathAssertions xpath(String expression, Object... args) {
 		EntityExchangeResult<byte[]> returnResult();
 	}
 
-	interface ResponseSpecMatcher extends Consumer<ResponseSpec> {}
 }

spring-test/src/test/java/org/springframework/test/web/reactive/server/samples/SoftAssertionTests.java

@@ -13,9 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.test.web.reactive.server.samples;
 
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.test.web.reactive.server.WebTestClient;
@@ -25,51 +25,46 @@
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 /**
- * Samples of tests using {@link WebTestClient} with soft assertions.
+ * Integration tests for {@link WebTestClient} with soft assertions.
  *
  * @author Michał Rowicki
- * @since 5.3
+ * @author Sam Brannen
+ * @since 5.3.10
  */
-public class SoftAssertionTests {
-
-	private WebTestClient client;
+class SoftAssertionTests {
 
-
-	@BeforeEach
-	public void setUp() throws Exception {
-		this.client = WebTestClient.bindToController(new TestController()).build();
-	}
+	private final WebTestClient webTestClient = WebTestClient.bindToController(new TestController()).build();
 
 
 	@Test
-	public void test() throws Exception {
-		this.client.get().uri("/test")
-				.exchange()
-				.expectAllSoftly(
-						exchange -> exchange.expectStatus().isOk(),
-						exchange -> exchange.expectBody(String.class).isEqualTo("It works!")
-				);
+	void expectAll() {
+		this.webTestClient.get().uri("/test").exchange()
+			.expectAll(
+				responseSpec -> responseSpec.expectStatus().isOk(),
+				responseSpec -> responseSpec.expectBody(String.class).isEqualTo("hello")
+			);
 	}
 
 	@Test
-	public void testAllFails() throws Exception {
+	void expectAllWithMultipleFailures() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				this.client.get().uri("/test")
-						.exchange()
-						.expectAllSoftly(
-								exchange -> exchange.expectStatus().isBadRequest(),
-								exchange -> exchange.expectBody(String.class).isEqualTo("It won't work :(")
-						)
-		).withMessage("[0] Status expected:<400 BAD_REQUEST> but was:<200 OK>\n[1] Response body expected:<It won't work :(> but was:<It works!>");
+			this.webTestClient.get().uri("/test").exchange()
+				.expectAll(
+					responseSpec -> responseSpec.expectStatus().isBadRequest(),
+					responseSpec -> responseSpec.expectStatus().isOk(),
+					responseSpec -> responseSpec.expectBody(String.class).isEqualTo("bogus")
+				)
+		).withMessage("Multiple Exceptions (2):\nStatus expected:<400 BAD_REQUEST> but was:<200 OK>\nResponse body expected:<bogus> but was:<hello>");
 	}
 
 
 	@RestController
 	static class TestController {
 
 		@GetMapping("/test")
-		public String handle() {
-			return "It works!";
+		String handle() {
+			return "hello";
 		}
 	}
+
 }

src/docs/asciidoc/testing/testing-webtestclient.adoc

@@ -262,19 +262,36 @@ To assert the response status and headers, use the following:
 .Java
 ----
 	client.get().uri("/persons/1")
-				.accept(MediaType.APPLICATION_JSON)
-				.exchange()
-				.expectStatus().isOk()
-				.expectHeader().contentType(MediaType.APPLICATION_JSON)
+		.accept(MediaType.APPLICATION_JSON)
+		.exchange()
+		.expectStatus().isOk()
+		.expectHeader().contentType(MediaType.APPLICATION_JSON);
 ----
 [source,kotlin,indent=0,subs="verbatim,quotes",role="secondary"]
 .Kotlin
 ----
 	client.get().uri("/persons/1")
-			.accept(MediaType.APPLICATION_JSON)
-			.exchange()
-			.expectStatus().isOk()
-			.expectHeader().contentType(MediaType.APPLICATION_JSON)
+		.accept(MediaType.APPLICATION_JSON)
+		.exchange()
+		.expectStatus().isOk()
+		.expectHeader().contentType(MediaType.APPLICATION_JSON)
+----
+
+If you would like for all expectations to be asserted even if one of them fails, you can
+use `expectAll(..)` instead of multiple chained `expect*(..)` calls. This feature is
+similar to the _soft assertions_ support in AssertJ and the `assertAll()` support in
+JUnit Jupiter.
+
+[source,java,indent=0,subs="verbatim,quotes",role="primary"]
+.Java
+----
+	client.get().uri("/persons/1")
+		.accept(MediaType.APPLICATION_JSON)
+		.exchange()
+		.expectAll(
+			spec -> spec.expectStatus().isOk(),
+			spec -> spec.expectHeader().contentType(MediaType.APPLICATION_JSON)
+		);
 ----
 
 You can then choose to decode the response body through one of the following: