Fix broken assertions on Windows

See gh-46334

Author: snicoll

core/spring-boot/src/test/java/org/springframework/boot/logging/log4j2/ElasticCommonSchemaStructuredLogFormatterTests.java

@@ -101,13 +101,14 @@ void shouldFormatException() {
 		expectedError.put("message", "Boom");
 		assertThat(error).containsAllEntriesOf(expectedError);
 		String stackTrace = (String) error.get("stack_trace");
-		assertThat(stackTrace).startsWith(
-				"""
-						java.lang.RuntimeException: Boom
-						\tat org.springframework.boot.logging.log4j2.ElasticCommonSchemaStructuredLogFormatterTests.shouldFormatException""");
-		assertThat(json).contains(
-				"""
-						java.lang.RuntimeException: Boom\\n\\tat org.springframework.boot.logging.log4j2.ElasticCommonSchemaStructuredLogFormatterTests.shouldFormatException""");
+		assertThat(stackTrace)
+			.startsWith(String.format("java.lang.RuntimeException: Boom%n\tat org.springframework.boot.logging.log4j2."
+					+ "ElasticCommonSchemaStructuredLogFormatterTests.shouldFormatException"));
+		assertThat(json).contains(String
+			.format("java.lang.RuntimeException: Boom%n\\tat org.springframework.boot.logging.log4j2."
+					+ "ElasticCommonSchemaStructuredLogFormatterTests.shouldFormatException")
+			.replace("\n", "\\n")
+			.replace("\r", "\\r"));
 	}
 
 	@Test

core/spring-boot/src/test/java/org/springframework/boot/logging/log4j2/GraylogExtendedLogFormatStructuredLogFormatterTests.java

@@ -136,21 +136,18 @@ void shouldFormatException() {
 		String fullMessage = (String) deserialized.get("full_message");
 		String stackTrace = (String) deserialized.get("_error_stack_trace");
 		assertThat(fullMessage).startsWith(
-				"""
-						message
-
-						java.lang.RuntimeException: Boom
-						\tat org.springframework.boot.logging.log4j2.GraylogExtendedLogFormatStructuredLogFormatterTests.shouldFormatException""");
-		assertThat(stackTrace).startsWith(
-				"""
-						java.lang.RuntimeException: Boom
-						\tat org.springframework.boot.logging.log4j2.GraylogExtendedLogFormatStructuredLogFormatterTests.shouldFormatException""");
-
+				"message\n\njava.lang.RuntimeException: Boom%n\tat org.springframework.boot.logging.log4j2.GraylogExtendedLogFormatStructuredLogFormatterTests.shouldFormatException"
+					.formatted());
 		assertThat(deserialized)
 			.containsAllEntriesOf(map("_error_type", "java.lang.RuntimeException", "_error_message", "Boom"));
+		assertThat(stackTrace).startsWith(
+				"java.lang.RuntimeException: Boom%n\tat org.springframework.boot.logging.log4j2.GraylogExtendedLogFormatStructuredLogFormatterTests.shouldFormatException"
+					.formatted());
 		assertThat(json).contains(
-				"""
-						message\\n\\njava.lang.RuntimeException: Boom\\n\\tat org.springframework.boot.logging.log4j2.GraylogExtendedLogFormatStructuredLogFormatterTests.shouldFormatException""");
+				"java.lang.RuntimeException: Boom%n\\tat org.springframework.boot.logging.log4j2.GraylogExtendedLogFormatStructuredLogFormatterTests.shouldFormatException"
+					.formatted()
+					.replace("\n", "\\n")
+					.replace("\r", "\\r"));
 	}
 
 	@Test

core/spring-boot/src/test/java/org/springframework/boot/logging/log4j2/LogstashStructuredLogFormatterTests.java

@@ -80,12 +80,13 @@ void shouldFormatException() {
 		Map<String, Object> deserialized = deserialize(json);
 		String stackTrace = (String) deserialized.get("stack_trace");
 		assertThat(stackTrace).startsWith(
-				"""
-						java.lang.RuntimeException: Boom
-						\tat org.springframework.boot.logging.log4j2.LogstashStructuredLogFormatterTests.shouldFormatException""");
+				"java.lang.RuntimeException: Boom%n\tat org.springframework.boot.logging.log4j2.LogstashStructuredLogFormatterTests.shouldFormatException"
+					.formatted());
 		assertThat(json).contains(
-				"""
-						java.lang.RuntimeException: Boom\\n\\tat org.springframework.boot.logging.log4j2.LogstashStructuredLogFormatterTests.shouldFormatException""");
+				"java.lang.RuntimeException: Boom%n\\tat org.springframework.boot.logging.log4j2.LogstashStructuredLogFormatterTests.shouldFormatException"
+					.formatted()
+					.replace("\n", "\\n")
+					.replace("\r", "\\r"));
 	}
 
 	@Test