Fix UTF-8 handling in ContentResultMatchers

Closes gh-23622

spring-test/src/main/java/org/springframework/test/web/servlet/result/ContentResultMatchers.java

@@ -16,6 +16,7 @@
 
 package org.springframework.test.web.servlet.result;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
 import javax.servlet.http.HttpServletResponse;
@@ -210,7 +211,7 @@ public class ContentResultMatchers {
 	 */
 	public ResultMatcher json(String jsonContent, boolean strict) {
 		return result -> {
-			String content = result.getResponse().getContentAsString();
+			String content = result.getResponse().getContentAsString(StandardCharsets.UTF_8);
 			this.jsonHelper.assertJsonEqual(jsonContent, content, strict);
 		};
 	}

spring-test/src/test/java/org/springframework/test/web/servlet/result/ContentResultMatchersTests.java

@@ -16,9 +16,12 @@
 
 package org.springframework.test.web.servlet.result;
 
+import java.nio.charset.StandardCharsets;
+
 import org.hamcrest.Matchers;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.http.MediaType;
 import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.test.web.servlet.StubMvcResult;
 
@@ -26,95 +29,92 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 /**
  * @author Rossen Stoyanchev
+ * @author Sebastien Deleuze
  */
 public class ContentResultMatchersTests {
 
 	@Test
 	public void typeMatches() throws Exception {
-		new ContentResultMatchers().contentType("application/json;charset=UTF-8").match(getStubMvcResult());
+		new ContentResultMatchers().contentType(MediaType.APPLICATION_JSON_VALUE).match(getStubMvcResult(CONTENT));
 	}
 
 	@Test
 	public void typeNoMatch() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().contentType("text/plain").match(getStubMvcResult()));
-	}
-
-	@Test
-	public void encoding() throws Exception {
-		new ContentResultMatchers().encoding("UTF-8").match(getStubMvcResult());
-	}
-
-	@Test
-	public void encodingNoMatch() throws Exception {
-		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().encoding("ISO-8859-1").match(getStubMvcResult()));
+				new ContentResultMatchers().contentType("text/plain").match(getStubMvcResult(CONTENT)));
 	}
 
 	@Test
 	public void string() throws Exception {
-		new ContentResultMatchers().string(new String(CONTENT.getBytes("UTF-8"))).match(getStubMvcResult());
+		new ContentResultMatchers().string(new String(CONTENT.getBytes("UTF-8"))).match(getStubMvcResult(CONTENT));
 	}
 
 	@Test
 	public void stringNoMatch() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().encoding("bogus").match(getStubMvcResult()));
+				new ContentResultMatchers().encoding("bogus").match(getStubMvcResult(CONTENT)));
 	}
 
 	@Test
 	public void stringMatcher() throws Exception {
 		String content = new String(CONTENT.getBytes("UTF-8"));
-		new ContentResultMatchers().string(Matchers.equalTo(content)).match(getStubMvcResult());
+		new ContentResultMatchers().string(Matchers.equalTo(content)).match(getStubMvcResult(CONTENT));
 	}
 
 	@Test
 	public void stringMatcherNoMatch() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().string(Matchers.equalTo("bogus")).match(getStubMvcResult()));
+				new ContentResultMatchers().string(Matchers.equalTo("bogus")).match(getStubMvcResult(CONTENT)));
 	}
 
 	@Test
 	public void bytes() throws Exception {
-		new ContentResultMatchers().bytes(CONTENT.getBytes("UTF-8")).match(getStubMvcResult());
+		new ContentResultMatchers().bytes(CONTENT.getBytes("UTF-8")).match(getStubMvcResult(CONTENT));
 	}
 
 	@Test
 	public void bytesNoMatch() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().bytes("bogus".getBytes()).match(getStubMvcResult()));
+				new ContentResultMatchers().bytes("bogus".getBytes()).match(getStubMvcResult(CONTENT)));
 	}
 
 	@Test
 	public void jsonLenientMatch() throws Exception {
-		new ContentResultMatchers().json("{\n \"foo\" : \"bar\"  \n}").match(getStubMvcResult());
-		new ContentResultMatchers().json("{\n \"foo\" : \"bar\"  \n}", false).match(getStubMvcResult());
+		new ContentResultMatchers().json("{\n \"foo\" : \"bar\"  \n}").match(getStubMvcResult(CONTENT));
+		new ContentResultMatchers().json("{\n \"foo\" : \"bar\"  \n}", false).match(getStubMvcResult(CONTENT));
 	}
 
 	@Test
 	public void jsonStrictMatch() throws Exception {
-		new ContentResultMatchers().json("{\n \"foo\":\"bar\",   \"foo array\":[\"foo\",\"bar\"] \n}", true).match(getStubMvcResult());
-		new ContentResultMatchers().json("{\n \"foo array\":[\"foo\",\"bar\"], \"foo\":\"bar\" \n}", true).match(getStubMvcResult());
+		new ContentResultMatchers().json("{\n \"foo\":\"bar\",   \"foo array\":[\"foo\",\"bar\"] \n}", true).match(getStubMvcResult(CONTENT));
+		new ContentResultMatchers().json("{\n \"foo array\":[\"foo\",\"bar\"], \"foo\":\"bar\" \n}", true).match(getStubMvcResult(CONTENT));
 	}
 
 	@Test
 	public void jsonLenientNoMatch() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().json("{\n\"fooo\":\"bar\"\n}").match(getStubMvcResult()));
+				new ContentResultMatchers().json("{\n\"fooo\":\"bar\"\n}").match(getStubMvcResult(CONTENT)));
 	}
 
 	@Test
 	public void jsonStrictNoMatch() throws Exception {
 		assertThatExceptionOfType(AssertionError.class).isThrownBy(() ->
-				new ContentResultMatchers().json("{\"foo\":\"bar\",   \"foo array\":[\"bar\",\"foo\"]}", true).match(getStubMvcResult()));
+				new ContentResultMatchers().json("{\"foo\":\"bar\",   \"foo array\":[\"bar\",\"foo\"]}", true).match(getStubMvcResult(CONTENT)));
+	}
+
+	@Test  // gh-23622
+	public void jsonUtf8Match() throws Exception {
+		new ContentResultMatchers().json("{\"name\":\"Jürgen\"}").match(getStubMvcResult(UTF8_CONTENT));
 	}
 
 	private static final String CONTENT = "{\"foo\":\"bar\",\"foo array\":[\"foo\",\"bar\"]}";
 
-	private StubMvcResult getStubMvcResult() throws Exception {
+	private static final String UTF8_CONTENT = "{\"name\":\"Jürgen\"}";
+
+	private StubMvcResult getStubMvcResult(String content) throws Exception {
 		MockHttpServletResponse response = new MockHttpServletResponse();
-		response.addHeader("Content-Type", "application/json; charset=UTF-8");
-		response.getWriter().print(new String(CONTENT.getBytes("UTF-8")));
+		response.addHeader("Content-Type", MediaType.APPLICATION_JSON_VALUE);
+		response.getOutputStream().write(content.getBytes(StandardCharsets.UTF_8));
 		return new StubMvcResult(null, null, null, null, null, null, response);
 	}