Avoid issues with system line separator in tests

See f10caf6aa6a3ec5bfe229bf403a267d2e022f60e

spring-core/src/testFixtures/java/org/springframework/core/testfixture/codec/AbstractEncoderTests.java

@@ -251,7 +251,7 @@ public abstract class AbstractEncoderTests<E extends Encoder<?>> extends Abstrac
 		return dataBuffer -> {
 			String actual = dataBuffer.toString(UTF_8);
 			release(dataBuffer);
-			assertThat(actual).isEqualTo(expected);
+			assertThat(actual).isEqualToNormalizingNewlines(expected);
 		};
 	}
 

spring-test/src/test/java/org/springframework/test/http/MediaTypeAssertTests.java

@@ -62,12 +62,10 @@ class MediaTypeAssertTests {
 
 	@Test
 	void isEqualInvalidStringShouldFail() {
-		String ls = System.lineSeparator();  // output below is different between Unix and Windows
 		assertThatExceptionOfType(AssertionError.class)
 				.isThrownBy(() -> assertThat(mediaType("application/json")).isEqualTo("example of a bad value"))
-				.withMessageContaining("[Media type]")
-				.withMessageEndingWith("To be a valid media type but got:" + ls +
-						"  \"Invalid mime type \"example of a bad value\": does not contain '/'\"" + ls);
+				.withMessageContainingAll("[Media type]", "To be a valid media type but got:",
+						"\"Invalid mime type \"example of a bad value\": does not contain '/'\"");
 	}
 
 	@Test
@@ -108,12 +106,10 @@ class MediaTypeAssertTests {
 
 	@Test
 	void isNotEqualInvalidStringShouldFail() {
-		String ls = System.lineSeparator();  // output below is different between Unix and Windows
 		assertThatExceptionOfType(AssertionError.class)
 				.isThrownBy(() -> assertThat(mediaType("application/json")).isNotEqualTo("example of a bad value"))
-				.withMessageContaining("[Media type]")
-				.withMessageEndingWith("To be a valid media type but got:" + ls +
-						"  \"Invalid mime type \"example of a bad value\": does not contain '/'\"" + ls);
+				.withMessageContainingAll("[Media type]", "To be a valid media type but got:",
+						"\"Invalid mime type \"example of a bad value\": does not contain '/'\"");
 	}
 
 	@Test
@@ -169,7 +165,7 @@ class MediaTypeAssertTests {
 	void isCompatibleWithStringAndEmptyExpected() {
 		assertThatExceptionOfType(AssertionError.class)
 				.isThrownBy(() -> assertThat(mediaType("application/json")).isCompatibleWith(""))
-				.withMessageContainingAll("Expecting:", "", "To be a valid media type but got:",
+				.withMessageContainingAll("Expecting:", "To be a valid media type but got:",
 						"'mimeType' must not be empty");
 	}
 

spring-web/src/test/java/org/springframework/http/codec/json/Jackson2JsonEncoderTests.java

@@ -262,9 +262,11 @@ class Jackson2JsonEncoderTests extends AbstractEncoderTests<Jackson2JsonEncoder>
 		ObjectMapper mapper = new ObjectMapper().configure(SerializationFeature.INDENT_OUTPUT, true);
 		this.encoder.registerObjectMappersForType(JacksonViewBean.class, map -> map.put(halMediaType, mapper));
 
-		String ls = System.lineSeparator();  // output below is different between Unix and Windows
 		testEncode(Mono.just(jacksonValue), type, halMediaType, Collections.emptyMap(), step -> step
-				.consumeNextWith(expectString("{" + ls + "  \"withView1\" : \"with\"" + ls + "}"))
+				.consumeNextWith(expectString("""
+					{
+					\s "withView1" : "with"
+					}"""))
 				.verifyComplete()
 		);
 	}

spring-web/src/test/java/org/springframework/http/converter/json/MappingJackson2HttpMessageConverterTests.java

@@ -63,8 +63,6 @@ import static org.assertj.core.api.Assertions.within;
  */
 class MappingJackson2HttpMessageConverterTests {
 
-	protected static final String NEWLINE_SYSTEM_PROPERTY = System.lineSeparator();
-
 	private final MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
 
 
@@ -369,8 +367,10 @@ class MappingJackson2HttpMessageConverterTests {
 		this.converter.writeInternal(bean, null, outputMessage);
 		String result = outputMessage.getBodyAsString(StandardCharsets.UTF_8);
 
-		assertThat(result).isEqualTo(("{" + NEWLINE_SYSTEM_PROPERTY +
-				"  \"name\" : \"Jason\"" + NEWLINE_SYSTEM_PROPERTY + "}"));
+		assertThat(result).isEqualToNormalizingNewlines("""
+			{
+			\s "name" : "Jason"
+			}""");
 	}
 
 	@Test

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandlerTests.java

@@ -81,8 +81,6 @@ import static org.springframework.web.testfixture.method.ResolvableMethod.on;
  */
 class ResponseEntityResultHandlerTests {
 
-	private static final String NEWLINE_SYSTEM_PROPERTY = System.lineSeparator();
-
 	private final ResponseEntityResultHandler resultHandler = createHandler();
 
 
@@ -458,10 +456,10 @@ class ResponseEntityResultHandlerTests {
 		handler.handleResult(exchange, result).block();
 
 		assertThat(exchange.getResponse().getHeaders().getContentType()).isEqualTo(halMediaType);
-		assertThat(exchange.getResponse().getBodyAsString().block()).isEqualTo(
-				"{" + NEWLINE_SYSTEM_PROPERTY +
-						"  \"name\" : \"Jason\"" + NEWLINE_SYSTEM_PROPERTY +
-						"}");
+		assertThat(exchange.getResponse().getBodyAsString().block()).isEqualToNormalizingNewlines("""
+				{
+				\s "name" : "Jason"
+				}""");
 	}
 
 	@Test  // gh-24539