RestTestClient correctly exposes the response body

Closes gh-35385

Author: rstoyanchev

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

@@ -286,33 +286,33 @@ public CookieAssertions expectCookie() {
 
 		@Override
 		public <B> BodySpec<B, ?> expectBody(Class<B> bodyType) {
-			B body = this.exchangeResult.getBody(bodyType);
+			B body = this.exchangeResult.getClientResponse().bodyTo(bodyType);
 			EntityExchangeResult<B> result = new EntityExchangeResult<>(this.exchangeResult, body);
 			return new DefaultBodySpec<>(result);
 		}
 
 		@Override
 		public <B> BodySpec<B, ?> expectBody(ParameterizedTypeReference<B> bodyType) {
-			B body = this.exchangeResult.getBody(bodyType);
+			B body = this.exchangeResult.getClientResponse().bodyTo(bodyType);
 			EntityExchangeResult<B> result = initExchangeResult(body);
 			return new DefaultBodySpec<>(result);
 		}
 
 		@Override
 		public BodyContentSpec expectBody() {
-			byte[] body = this.exchangeResult.getBody(byte[].class);
+			byte[] body = this.exchangeResult.getClientResponse().bodyTo(byte[].class);
 			EntityExchangeResult<byte[]> result = initExchangeResult(body);
 			return new DefaultBodyContentSpec(result);
 		}
 
 		@Override
 		public <T> EntityExchangeResult<T> returnResult(Class<T> elementClass) {
-			return initExchangeResult(this.exchangeResult.getBody(elementClass));
+			return initExchangeResult(this.exchangeResult.getClientResponse().bodyTo(elementClass));
 		}
 
 		@Override
 		public <T> EntityExchangeResult<T> returnResult(ParameterizedTypeReference<T> elementTypeRef) {
-			return initExchangeResult(this.exchangeResult.getBody(elementTypeRef));
+			return initExchangeResult(this.exchangeResult.getClientResponse().bodyTo(elementTypeRef));
 		}
 
 		private <B> EntityExchangeResult<B> initExchangeResult(@Nullable B body) {
@@ -412,7 +412,7 @@ private static class DefaultBodyContentSpec implements BodyContentSpec {
 		@Override
 		public EntityExchangeResult<Void> isEmpty() {
 			this.result.assertWithDiagnostics(() ->
-					AssertionErrors.assertTrue("Expected empty body", this.result.getBody(byte[].class) == null));
+					AssertionErrors.assertTrue("Expected empty body", this.result.getResponseBody() == null));
 			return new EntityExchangeResult<>(this.result, null);
 		}
 

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

@@ -29,7 +29,6 @@
 import org.apache.commons.logging.LogFactory;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpRequest;
@@ -160,14 +159,11 @@ private static ResponseCookie toResponseCookie(HttpCookie cookie, @Nullable Stri
 				.build();
 	}
 
-	@Nullable
-	public <T> T getBody(Class<T> bodyType) {
-		return this.clientResponse.bodyTo(bodyType);
-	}
-
-	@Nullable
-	public <T> T getBody(ParameterizedTypeReference<T> bodyType) {
-		return this.clientResponse.bodyTo(bodyType);
+	/**
+	 * Provide access to the response. For internal use to decode the body.
+	 */
+	ConvertibleClientHttpResponse getClientResponse() {
+		return this.clientResponse;
 	}
 
 	/**

spring-test/src/test/java/org/springframework/test/web/servlet/client/samples/bind/RouterFunctionTests.java

@@ -16,13 +16,17 @@
 
 package org.springframework.test.web.servlet.client.samples.bind;
 
+import java.nio.charset.StandardCharsets;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.test.web.servlet.client.EntityExchangeResult;
 import org.springframework.test.web.servlet.client.RestTestClient;
 import org.springframework.web.servlet.function.RouterFunction;
 import org.springframework.web.servlet.function.ServerResponse;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.web.servlet.function.RequestPredicates.GET;
 import static org.springframework.web.servlet.function.RouterFunctions.route;
 
@@ -50,4 +54,15 @@ void test() {
 				.expectBody(String.class).isEqualTo("It works!");
 	}
 
+	@Test
+	void testEntityExchangeResult() {
+		EntityExchangeResult<byte[]> result = this.testClient.get().uri("/test")
+				.exchange()
+				.expectStatus().isOk()
+				.expectBody()
+				.returnResult();
+
+		assertThat(result.getResponseBody()).isEqualTo("It works!".getBytes(StandardCharsets.UTF_8));
+	}
+
 }