Move response body directly in AbstractMockHttpServletResponseAssert

This commit removes ResponseBodyAssert and rather offers first-class
access support for the response body at the root level using bodyText(),
bodyJson(), and body().

This avoids a double navigation to assert the response body.

See gh-32712

spring-test/src/main/java/org/springframework/test/json/AbstractJsonContentAssert.java

@@ -52,7 +52,10 @@
  * assertions} on the value.
  *
  * <p>Also support comparing the JSON document against a target, using
- * {@linkplain JSONCompare JSON Assert}.
+ * {@linkplain JSONCompare JSON Assert}. Resources that are loaded from
+ * the classpath can be relative if a {@linkplain #withResourceLoadClass(Class)
+ * class} is provided. By default, {@code UTF-8} is used to load resources
+ * but this can be overridden using {@link #withCharset(Charset)}.
  *
  * @author Stephane Nicoll
  * @author Phillip Webb
@@ -71,28 +74,27 @@ public abstract class AbstractJsonContentAssert<SELF extends AbstractJsonContent
 	@Nullable
 	private final GenericHttpMessageConverter<Object> jsonMessageConverter;
 
-	private final JsonLoader jsonLoader;
+	@Nullable
+	private Class<?> resourceLoadClass;
+
+	@Nullable
+	private Charset charset;
+
+	private JsonLoader jsonLoader;
 
 	/**
 	 * Create an assert for the given JSON document.
 	 * <p>Path can be converted to a value object using the given
 	 * {@linkplain GenericHttpMessageConverter json message converter}.
-	 * <p>Resources to match can be loaded relative to the given
-	 * {@code resourceLoadClass}. If not specified, resources must always be
-	 * absolute. A specific {@link Charset} can be provided if {@code UTF-8} is
-	 * not suitable.
 	 * @param json the JSON document to assert
 	 * @param jsonMessageConverter the converter to use
-	 * @param resourceLoadClass the class used to load resources
-	 * @param charset the charset of the JSON resources
 	 * @param selfType the implementation type of this assert
 	 */
 	protected AbstractJsonContentAssert(@Nullable String json,
-			@Nullable GenericHttpMessageConverter<Object> jsonMessageConverter, @Nullable Class<?> resourceLoadClass,
-			@Nullable Charset charset, Class<?> selfType) {
+			@Nullable GenericHttpMessageConverter<Object> jsonMessageConverter, Class<?> selfType) {
 		super(json, selfType);
 		this.jsonMessageConverter = jsonMessageConverter;
-		this.jsonLoader = new JsonLoader(resourceLoadClass, charset);
+		this.jsonLoader = new JsonLoader(null, null);
 		as("JSON content");
 	}
 
@@ -376,6 +378,31 @@ public SELF isNotStrictlyEqualTo(Resource expected) {
 		return isNotEqualTo(expected, JSONCompareMode.STRICT);
 	}
 
+	/**
+	 * Override the class used to load resources. Resources can be loaded from
+	 * an absolute location or relative to tpe specified class. For instance,
+	 * specifying {@code com.example.MyClass} as the resource class allows you
+	 * to use "my-file.json" to load {@code /com/example/my-file.json}.
+	 * @param resourceLoadClass the class used to load resources or {@code null}
+	 * to only use absolute paths.
+	 */
+	public SELF withResourceLoadClass(@Nullable Class<?> resourceLoadClass) {
+		this.resourceLoadClass = resourceLoadClass;
+		this.jsonLoader = new JsonLoader(resourceLoadClass, this.charset);
+		return this.myself;
+	}
+
+	/**
+	 * Override the {@link Charset} to use to load resources. By default,
+	 * resources are loaded using {@code UTF-8}.
+	 * @param charset the charset to use, or {@code null} to use the default
+	 */
+	public SELF withCharset(@Nullable Charset charset) {
+		this.charset = charset;
+		this.jsonLoader = new JsonLoader(this.resourceLoadClass, charset);
+		return this.myself;
+	}
+
 
 	private JSONCompareResult compare(@Nullable CharSequence expectedJson, JSONCompareMode compareMode) {
 		return compare(this.actual, expectedJson, (actualJsonString, expectedJsonString) ->

spring-test/src/main/java/org/springframework/test/json/JsonContent.java

@@ -55,7 +55,7 @@ public final class JsonContent implements AssertProvider<JsonContentAssert> {
 	 */
 	@Override
 	public JsonContentAssert assertThat() {
-		return new JsonContentAssert(this.json, null, this.resourceLoadClass, null);
+		return new JsonContentAssert(this.json, null).withResourceLoadClass(this.resourceLoadClass);
 	}
 
 	/**

spring-test/src/main/java/org/springframework/test/json/JsonContentAssert.java

@@ -16,8 +16,6 @@
 
 package org.springframework.test.json;
 
-import java.nio.charset.Charset;
-
 import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.lang.Nullable;
 
@@ -33,19 +31,11 @@ public class JsonContentAssert extends AbstractJsonContentAssert<JsonContentAsse
 	 * Create an assert for the given JSON document.
 	 * <p>Path can be converted to a value object using the given
 	 * {@linkplain GenericHttpMessageConverter json message converter}.
-	 * <p>Resources to match can be loaded relative to the given
-	 * {@code resourceLoadClass}. If not specified, resources must always be
-	 * absolute. A specific {@link Charset} can be provided if {@code UTF-8} is
-	 * not suitable.
 	 * @param json the JSON document to assert
 	 * @param jsonMessageConverter the converter to use
-	 * @param resourceLoadClass the class used to load resources
-	 * @param charset the charset of the JSON resources
 	 */
-	public JsonContentAssert(@Nullable String json, @Nullable GenericHttpMessageConverter<Object> jsonMessageConverter,
-			@Nullable Class<?> resourceLoadClass, @Nullable Charset charset) {
-
-		super(json, jsonMessageConverter, resourceLoadClass, charset, JsonContentAssert.class);
+	public JsonContentAssert(@Nullable String json, @Nullable GenericHttpMessageConverter<Object> jsonMessageConverter) {
+		super(json, jsonMessageConverter, JsonContentAssert.class);
 	}
 
 }

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

@@ -18,9 +18,16 @@
 
 import java.nio.charset.Charset;
 
+import org.assertj.core.api.AbstractByteArrayAssert;
+import org.assertj.core.api.AbstractStringAssert;
+import org.assertj.core.api.Assertions;
+import org.assertj.core.api.ByteArrayAssert;
+
 import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.lang.Nullable;
 import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.test.json.AbstractJsonContentAssert;
+import org.springframework.test.json.JsonContentAssert;
 import org.springframework.test.web.UriAssert;
 
 /**
@@ -45,22 +52,62 @@ protected AbstractMockHttpServletResponseAssert(
 		this.jsonMessageConverter = jsonMessageConverter;
 	}
 
+
 	/**
-	 * Return a new {@linkplain ResponseBodyAssert assertion} object that uses
-	 * the response body as the object to test. The returned assertion object
-	 * provides access to the raw byte array, a String value decoded using the
-	 * response's character encoding, and dedicated JSON testing support.
+	 * Return a new {@linkplain AbstractStringAssert assertion} object that uses
+	 * the response body converted to text as the object to test.
 	 * <p>Examples: <pre><code class='java'>
 	 * // Check that the response body is equal to "Hello World":
-	 * assertThat(response).body().isEqualTo("Hello World");
+	 * assertThat(response).bodyText().isEqualTo("Hello World");
+	 * </code></pre>
+	 */
+	public AbstractStringAssert<?> bodyText() {
+		return Assertions.assertThat(readBody());
+	}
+
+	/**
+	 * Return a new {@linkplain AbstractJsonContentAssert assertion} object that
+	 * uses the response body converted to text as the object to test. Compared
+	 * to {@link #bodyText()}, the assertion object provides dedicated JSON
+	 * support.
+	 * <p>Examples: <pre><code class='java'>
+	 * // Check that the response body is strictly equal to the content of
+	 * // "/com/acme/sample/person-created.json":
+	 * assertThat(response).bodyJson()
+	 *         .isStrictlyEqualToJson("/com/acme/sample/person-created.json");
+	 *
+	 * // Check that the response is strictly equal to the content of the
+	 * // specified file located in the same package as the PersonController:
+	 * assertThat(response).bodyJson().withResourceLoadClass(PersonController.class)
+	 *         .isStrictlyEqualToJson("person-created.json");
+	 * </code></pre>
+	 * The returned assert object also supports JSON path expressions.
+	 * <p>Examples: <pre><code class='java'>
+	 * // Check that the JSON document does not have an "error" element
+	 * assertThat(response).bodyJson().doesNotHavePath("$.error");
 	 *
-	 * // Check that the response body is strictly equal to the content of "test.json":
-	 * assertThat(response).body().json().isStrictlyEqualToJson("test.json");
+	 * // Check that the JSON document as a top level "message" element
+	 * assertThat(response).bodyJson()
+	 *         .extractingPath("$.message").asString().isEqualTo("hello");
 	 * </code></pre>
 	 */
-	public ResponseBodyAssert body() {
-		return new ResponseBodyAssert(getResponse().getContentAsByteArray(),
-				Charset.forName(getResponse().getCharacterEncoding()), this.jsonMessageConverter);
+	public AbstractJsonContentAssert<?> bodyJson() {
+		return new JsonContentAssert(readBody(), this.jsonMessageConverter);
+	}
+
+	private String readBody() {
+		return new String(getResponse().getContentAsByteArray(),
+				Charset.forName(getResponse().getCharacterEncoding()));
+	}
+
+	/**
+	 * Return a new {@linkplain AbstractByteArrayAssert assertion} object that
+	 * uses the response body as the object to test.
+	 * @see #bodyText()
+	 * @see #bodyJson()
+	 */
+	public AbstractByteArrayAssert<?> body() {
+		return new ByteArrayAssert(getResponse().getContentAsByteArray());
 	}
 
 	/**
@@ -89,6 +136,14 @@ public UriAssert redirectedUrl() {
 		return new UriAssert(getResponse().getRedirectedUrl(), "Redirected URL");
 	}
 
+	/**
+	 * Verify that the response body is equal to the given value.
+	 */
+	public SELF hasBodyTextEqualTo(String bodyText) {
+		bodyText().isEqualTo(bodyText);
+		return this.myself;
+	}
+
 	/**
 	 * Verify that the forwarded URL is equal to the given value.
 	 * @param forwardedUrl the expected forwarded URL (can be null)