JSON content and JsonPath support for WebTestClient

Issue: SPR-15420

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

@@ -40,6 +40,7 @@ import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.http.client.reactive.ClientHttpConnector;
 import org.springframework.http.client.reactive.ClientHttpRequest;
+import org.springframework.test.util.JsonExpectationsHelper;
 import org.springframework.util.Assert;
 import org.springframework.util.MimeType;
 import org.springframework.util.MultiValueMap;
@@ -502,6 +503,24 @@ class DefaultWebTestClient implements WebTestClient {
 			return new EntityExchangeResult<>(this.result, null);
 		}
 
+		@Override
+		public BodyContentSpec json(String json) {
+			this.result.assertWithDiagnostics(() -> {
+				try {
+					new JsonExpectationsHelper().assertJsonEqual(json, getBodyAsString());
+				}
+				catch (Exception ex) {
+					throw new AssertionError("JSON parsing error", ex);
+				}
+			});
+			return this;
+		}
+
+		@Override
+		public JsonPathAssertions jsonPath(String expression, Object... args) {
+			return new JsonPathAssertions(this, expression, args);
+		}
+
 		@Override
 		public BodyContentSpec consumeAsStringWith(Consumer<String> consumer) {
 			this.result.assertWithDiagnostics(() -> consumer.accept(getBodyAsString()));

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

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2002-2017 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
+ *
+ *      http://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.reactive.server;
+
+import org.springframework.test.util.JsonPathExpectationsHelper;
+
+
+/**
+ * <a href="https://github.com/jayway/JsonPath">JsonPath</a> assertions.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ * @see <a href="https://github.com/jayway/JsonPath">https://github.com/jayway/JsonPath</a>
+ */
+public class JsonPathAssertions {
+
+	private final WebTestClient.BodyContentSpec bodySpec;
+
+	private final JsonPathExpectationsHelper pathHelper;
+
+
+	JsonPathAssertions(WebTestClient.BodyContentSpec spec, String expression, Object... args) {
+		this.bodySpec = spec;
+		this.pathHelper = new JsonPathExpectationsHelper(expression, args);
+	}
+
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValue(String, Object)}.
+	 */
+	public WebTestClient.BodyContentSpec isEqualTo(Object expectedValue) {
+		this.bodySpec.consumeAsStringWith(body -> {
+			this.pathHelper.assertValue(body, expectedValue);
+		});
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#exists(String)}.
+	 */
+	public WebTestClient.BodyContentSpec exists() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::exists);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#doesNotExist(String)}.
+	 */
+	public WebTestClient.BodyContentSpec doesNotExist() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::doesNotExist);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValueIsEmpty(String)}.
+	 */
+	public WebTestClient.BodyContentSpec isEmpty() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::assertValueIsEmpty);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValueIsNotEmpty(String)}.
+	 */
+	public WebTestClient.BodyContentSpec isNotEmpty() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::assertValueIsNotEmpty);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValueIsBoolean(String)}.
+	 */
+	public WebTestClient.BodyContentSpec isBoolean() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::assertValueIsBoolean);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValueIsNumber(String)}.
+	 */
+	public WebTestClient.BodyContentSpec isNumber() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::assertValueIsNumber);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValueIsArray(String)}.
+	 */
+	public WebTestClient.BodyContentSpec isArray() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::assertValueIsArray);
+		return this.bodySpec;
+	}
+
+	/**
+	 * Applies {@link JsonPathExpectationsHelper#assertValueIsMap(String)}.
+	 */
+	public WebTestClient.BodyContentSpec isMap() {
+		this.bodySpec.consumeAsStringWith(this.pathHelper::assertValueIsMap);
+		return this.bodySpec;
+	}
+
+}

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

@@ -598,11 +598,31 @@ public interface WebTestClient {
 	interface BodyContentSpec {
 
 		/**
-		 * Consume the body and verify it is empty.
-		 * @return the exchange result
+		 * Assert the response body is empty and return the exchange result.
 		 */
 		EntityExchangeResult<Void> isEmpty();
 
+		/**
+		 * Parse the expected and actual response content as JSON and perform a
+		 * "lenient" comparison verifying the same attribute-value pairs.
+		 * <p>Use of this option requires the
+		 * <a href="http://jsonassert.skyscreamer.org/">JSONassert<a/> library
+		 * on to be on the classpath.
+		 * @param expectedJson the expected JSON content.
+		 */
+		BodyContentSpec json(String expectedJson);
+
+		/**
+		 * Access to response body assertions using a
+		 * <a href="https://github.com/jayway/JsonPath">JsonPath</a> expression
+		 * to inspect a specific subset of the body.
+		 * <p>The JSON path expression can be a parameterized string using
+		 * formatting specifiers as defined in {@link String#format}.
+		 * @param expression the JsonPath expression
+		 * @param args arguments to parameterize the expression
+		 */
+		JsonPathAssertions jsonPath(String expression, Object... args);
+
 		/**
 		 * Assert the response body content converted to a String with the given
 		 * {@link Consumer}. The String is created with the {@link Charset} from

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

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2002-2017 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
+ *
+ *      http://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.reactive.server.samples;
+
+import org.junit.Test;
+import reactor.core.publisher.Flux;
+
+import org.springframework.http.MediaType;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Sample tests asserting JSON response content.
+ *
+ * @author Rossen Stoyanchev
+ */
+public class JsonContentTests {
+
+	private final WebTestClient client = WebTestClient.bindToController(new PersonController()).build();
+
+
+	@Test
+	public void jsonContent() throws Exception {
+		this.client.get().uri("/persons")
+				.accept(MediaType.APPLICATION_JSON_UTF8)
+				.exchange()
+				.expectStatus().isOk()
+				.expectBody().json("[{\"name\":\"Jane\"},{\"name\":\"Jason\"},{\"name\":\"John\"}]");
+	}
+
+	@Test
+	public void jsonPathIsEqualTo() throws Exception {
+		this.client.get().uri("/persons")
+				.accept(MediaType.APPLICATION_JSON_UTF8)
+				.exchange()
+				.expectStatus().isOk()
+				.expectBody()
+				.jsonPath("$[0].name").isEqualTo("Jane")
+				.jsonPath("$[1].name").isEqualTo("Jason")
+				.jsonPath("$[2].name").isEqualTo("John");
+	}
+
+
+	@RestController
+	@SuppressWarnings("unused")
+	static class PersonController {
+
+		@GetMapping("/persons")
+		Flux<Person> getPersons() {
+			return Flux.just(new Person("Jane"), new Person("Jason"), new Person("John"));
+		}
+	}
+
+}

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

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2002-2017 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
+ *
+ *      http://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.reactive.server.samples;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+class Person {
+
+	private final String name;
+
+	@JsonCreator
+	public Person(@JsonProperty("name") String name) {
+		this.name = name;
+	}
+
+	public String getName() {
+		return this.name;
+	}
+
+	@Override
+	public boolean equals(Object other) {
+		if (this == other) return true;
+		if (other == null || getClass() != other.getClass()) return false;
+		Person person = (Person) other;
+		return getName().equals(person.getName());
+	}
+
+	@Override
+	public int hashCode() {
+		return getName().hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return "Person[name='" + name + "']";
+	}
+
+}

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

@@ -22,8 +22,6 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-import com.fasterxml.jackson.annotation.JsonCreator;
-import com.fasterxml.jackson.annotation.JsonProperty;
 import org.junit.Test;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -169,36 +167,4 @@ public class ResponseEntityTests {
 		}
 	}
 
-	static class Person {
-
-		private final String name;
-
-		@JsonCreator
-		public Person(@JsonProperty("name") String name) {
-			this.name = name;
-		}
-
-		public String getName() {
-			return this.name;
-		}
-
-		@Override
-		public boolean equals(Object other) {
-			if (this == other) return true;
-			if (other == null || getClass() != other.getClass()) return false;
-			Person person = (Person) other;
-			return getName().equals(person.getName());
-		}
-
-		@Override
-		public int hashCode() {
-			return getName().hashCode();
-		}
-
-		@Override
-		public String toString() {
-			return "Person[name='" + name + "']";
-		}
-	}
-
 }