diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfigurationTests.java b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfigurationTests.java
index 42af59258d7..3c892cc4880 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfigurationTests.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/neo4j/Neo4jAutoConfigurationTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -284,7 +284,7 @@ class Neo4jAutoConfigurationTests {
 	@Test
 	void securityWithCustomCertificates(@TempDir File directory) throws IOException {
 		File certFile = new File(directory, "neo4j-driver.cert");
-		assertThat(certFile.createNewFile());
+		assertThat(certFile.createNewFile()).isTrue();
 
 		Neo4jProperties properties = new Neo4jProperties();
 		properties.getSecurity().setTrustStrategy(TrustStrategy.TRUST_CUSTOM_CA_SIGNED_CERTIFICATES);
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/buildinfo/BuildInfoIntegrationTests.java b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/buildinfo/BuildInfoIntegrationTests.java
index e25342e8974..31e4f41de71 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/buildinfo/BuildInfoIntegrationTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/buildinfo/BuildInfoIntegrationTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -80,7 +80,7 @@ class BuildInfoIntegrationTests {
 		Properties second = buildInfoProperties();
 		String secondBuildTime = second.getProperty("build.time");
 		assertThat(secondBuildTime).isNotNull();
-		assertThat(Instant.parse(firstBuildTime).isBefore(Instant.parse(secondBuildTime)));
+		assertThat(Instant.parse(firstBuildTime)).isBefore(Instant.parse(secondBuildTime));
 	}
 
 	@TestTemplate
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootBuildImageRegistryIntegrationTests.java b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootBuildImageRegistryIntegrationTests.java
index 841b57c9e1e..de7531dcec1 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootBuildImageRegistryIntegrationTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootBuildImageRegistryIntegrationTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -61,7 +61,7 @@ public class BootBuildImageRegistryIntegrationTests {
 
 	@BeforeEach
 	void setUp() {
-		assertThat(registry.isRunning());
+		assertThat(registry.isRunning()).isTrue();
 		this.registryAddress = registry.getHost() + ":" + registry.getFirstMappedPort();
 	}
 
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AbstractArchiveIntegrationTests.java b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AbstractArchiveIntegrationTests.java
index 87991fa6941..05cc9a7764d 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AbstractArchiveIntegrationTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AbstractArchiveIntegrationTests.java
@@ -98,7 +98,7 @@ abstract class AbstractArchiveIntegrationTests {
 
 		private JarAssert(File actual) {
 			super(actual, JarAssert.class);
-			assertThat(actual.exists());
+			assertThat(actual).exists();
 		}
 
 		JarAssert doesNotHaveEntryWithName(String name) {
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/BuildImageRegistryIntegrationTests.java b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/BuildImageRegistryIntegrationTests.java
index 654d070d291..d1b0bda10af 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/BuildImageRegistryIntegrationTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/BuildImageRegistryIntegrationTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -55,7 +55,7 @@ public class BuildImageRegistryIntegrationTests extends AbstractArchiveIntegrati
 
 	@BeforeEach
 	void setUp() {
-		assertThat(registry.isRunning());
+		assertThat(registry.isRunning()).isTrue();
 		this.dockerClient = registry.getDockerClient();
 		this.registryAddress = registry.getHost() + ":" + registry.getFirstMappedPort();
 	}
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java
index b818d3bcb53..b70b13a0d40 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -1228,10 +1228,10 @@ class SpringApplicationTests {
 		application.addListeners(listener);
 		application.run();
 		ApplicationStartingEvent startingEvent = listener.getEvent(ApplicationStartingEvent.class);
-		assertThat(startingEvent.getBootstrapContext().get(String.class));
+		assertThat(startingEvent.getBootstrapContext().get(String.class)).isEqualTo("boot");
 		ApplicationEnvironmentPreparedEvent environmentPreparedEvent = listener
 				.getEvent(ApplicationEnvironmentPreparedEvent.class);
-		assertThat(environmentPreparedEvent.getBootstrapContext().get(String.class));
+		assertThat(environmentPreparedEvent.getBootstrapContext().get(String.class)).isEqualTo("boot");
 	}
 
 	@Test
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/rsocket/netty/NettyRSocketServerFactoryTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/rsocket/netty/NettyRSocketServerFactoryTests.java
index 4e82dddf779..06a52b391b3 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/rsocket/netty/NettyRSocketServerFactoryTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/rsocket/netty/NettyRSocketServerFactoryTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -54,7 +54,6 @@ import org.springframework.messaging.rsocket.RSocketStrategies;
 import org.springframework.util.SocketUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.will;
 import static org.mockito.Mockito.inOrder;
@@ -203,7 +202,7 @@ class NettyRSocketServerFactoryTests {
 		String payload = "test payload";
 		Mono<String> responseMono = this.requester.route("test").data(payload).retrieveMono(String.class);
 		StepVerifier.create(responseMono)
-				.verifyErrorSatisfies((ex) -> assertThatExceptionOfType(ClosedChannelException.class));
+				.verifyErrorSatisfies((ex) -> assertThat(ex).isInstanceOf(ClosedChannelException.class));
 	}
 
 	private RSocketRequester createRSocketTcpClient() {
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java
index 97a95a4e795..d35cff231df 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java
@@ -40,7 +40,7 @@ public class Jetty10ServletWebServerFactoryTests extends JettyServletWebServerFa
 	@Test
 	protected void correctVersionOfJettyUsed() {
 		String jettyVersion = ErrorHandler.class.getPackage().getImplementationVersion();
-		assertThat(jettyVersion.startsWith("10.0"));
+		assertThat(jettyVersion).startsWith("10.0");
 	}
 
 	@Override