Use AssertJ's fail, not JUnit's

This commit also updates Checkstyle to prevent use of JUnit's
assertions from being reintroduced.

See gh-37655

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/ValidationFailureAnalyzerTests.java

@@ -30,7 +30,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link ValidationFailureAnalyzer}.

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/admin/SpringApplicationAdminJmxAutoConfigurationTests.java

@@ -43,7 +43,7 @@ import org.springframework.jmx.export.MBeanExporter;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link SpringApplicationAdminJmxAutoConfiguration}.

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jdbc/TomcatDataSourceConfigurationTests.java

@@ -34,7 +34,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.EnableMBeanExport;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link TomcatDataSourceConfiguration}.

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/websocket/servlet/WebSocketMessagingAutoConfigurationTests.java

@@ -69,7 +69,7 @@ import org.springframework.web.socket.sockjs.client.Transport;
 import org.springframework.web.socket.sockjs.client.WebSocketTransport;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link WebSocketMessagingAutoConfiguration}.

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandlerTests.java

@@ -21,7 +21,7 @@ import java.util.concurrent.CountDownLatch;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link SilentExitExceptionHandler}.

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/PropertyMapperTests.java

@@ -18,11 +18,11 @@ package org.springframework.boot.context.properties;
 
 import java.util.function.Supplier;
 
-import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link PropertyMapper}.
@@ -56,7 +56,7 @@ class PropertyMapperTests {
 
 	@Test
 	void fromValueAlwaysApplyingWhenNonNullShouldAlwaysApplyNonNullToSource() {
-		this.map.alwaysApplyingWhenNonNull().from((String) null).toCall(Assertions::fail);
+		this.map.alwaysApplyingWhenNonNull().from((String) null).toCall(() -> fail(null));
 	}
 
 	@Test
@@ -100,14 +100,14 @@ class PropertyMapperTests {
 
 	@Test
 	void whenNonNullWhenSuppliedNullShouldNotMap() {
-		this.map.from(() -> null).whenNonNull().as(String::valueOf).toCall(Assertions::fail);
+		this.map.from(() -> null).whenNonNull().as(String::valueOf).toCall(() -> fail(null));
 	}
 
 	@Test
 	void whenNonNullWhenSuppliedThrowsNullPointerExceptionShouldNotMap() {
 		this.map.from(() -> {
 			throw new NullPointerException();
-		}).whenNonNull().as(String::valueOf).toCall(Assertions::fail);
+		}).whenNonNull().as(String::valueOf).toCall(() -> fail(null));
 	}
 
 	@Test
@@ -118,7 +118,7 @@ class PropertyMapperTests {
 
 	@Test
 	void whenTrueWhenValueIsFalseShouldNotMap() {
-		this.map.from(false).whenTrue().toCall(Assertions::fail);
+		this.map.from(false).whenTrue().toCall(() -> fail(null));
 	}
 
 	@Test
@@ -129,17 +129,17 @@ class PropertyMapperTests {
 
 	@Test
 	void whenFalseWhenValueIsTrueShouldNotMap() {
-		this.map.from(true).whenFalse().toCall(Assertions::fail);
+		this.map.from(true).whenFalse().toCall(() -> fail(null));
 	}
 
 	@Test
 	void whenHasTextWhenValueIsNullShouldNotMap() {
-		this.map.from(() -> null).whenHasText().toCall(Assertions::fail);
+		this.map.from(() -> null).whenHasText().toCall(() -> fail(null));
 	}
 
 	@Test
 	void whenHasTextWhenValueIsEmptyShouldNotMap() {
-		this.map.from("").whenHasText().toCall(Assertions::fail);
+		this.map.from("").whenHasText().toCall(() -> fail(null));
 	}
 
 	@Test
@@ -156,7 +156,7 @@ class PropertyMapperTests {
 
 	@Test
 	void whenEqualToWhenValueIsNotEqualShouldNotMatch() {
-		this.map.from("123").whenEqualTo("321").toCall(Assertions::fail);
+		this.map.from("123").whenEqualTo("321").toCall(() -> fail(null));
 	}
 
 	@Test
@@ -168,7 +168,7 @@ class PropertyMapperTests {
 	@Test
 	void whenInstanceOfWhenValueIsNotTargetTypeShouldNotMatch() {
 		Supplier<Number> supplier = () -> 123L;
-		this.map.from(supplier).whenInstanceOf(Double.class).toCall(Assertions::fail);
+		this.map.from(supplier).whenInstanceOf(Double.class).toCall(() -> fail(null));
 	}
 
 	@Test
@@ -179,7 +179,7 @@ class PropertyMapperTests {
 
 	@Test
 	void whenWhenValueDoesNotMatchShouldNotMap() {
-		this.map.from("123").when("321"::equals).toCall(Assertions::fail);
+		this.map.from("123").when("321"::equals).toCall(() -> fail(null));
 	}
 
 	@Test
@@ -197,12 +197,12 @@ class PropertyMapperTests {
 
 	@Test
 	void alwaysApplyingWhenNonNullShouldAlwaysApplyNonNullToSource() {
-		this.map.alwaysApplyingWhenNonNull().from(() -> null).toCall(Assertions::fail);
+		this.map.alwaysApplyingWhenNonNull().from(() -> null).toCall(() -> fail(null));
 	}
 
 	@Test
 	void whenWhenValueNotMatchesShouldSupportChainedCalls() {
-		this.map.from("123").when("456"::equals).when("123"::equals).toCall(Assertions::fail);
+		this.map.from("123").when("456"::equals).when("123"::equals).toCall(() -> fail(null));
 	}
 
 	@Test

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/diagnostics/analyzer/BeanCurrentlyInCreationFailureAnalyzerTests.java

@@ -37,7 +37,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link BeanCurrentlyInCreationFailureAnalyzer}.

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/diagnostics/analyzer/BeanNotOfRequiredTypeFailureAnalyzerTests.java

@@ -29,7 +29,7 @@ import org.springframework.scheduling.annotation.Async;
 import org.springframework.scheduling.annotation.EnableAsync;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 /**
  * Tests for {@link BeanNotOfRequiredTypeFailureAnalyzer}.

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/util/LambdaSafeTests.java

@@ -29,7 +29,7 @@ import org.springframework.boot.util.LambdaSafe.InvocationResult;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.contains;
 import static org.mockito.BDDMockito.given;

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -149,7 +149,7 @@ import static org.assertj.core.api.Assertions.assertThatIOException;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.BDDMockito.then;

src/checkstyle/checkstyle.xml

@@ -32,7 +32,7 @@
 		</module>
 		<module name="com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineJavaCheck">
 			<property name="maximum" value="0"/>
-			<property name="format" value="org\.junit\.Assert\.assert" />
+			<property name="format" value="org\.junit\.Assert|org\.junit\.jupiter\.api\.Assertions" />
 			<property name="message"
 				value="Please use AssertJ imports." />
 			<property name="ignoreComments" value="true" />