Merge pull request #15791 from Christoph Dreis

* gh-15791:
  Polish "Test the Gradle plugin against Gradle 4.10.3 and 5.1.1"
  Test the Gradle plugin against Gradle 4.10.3 and 5.1.1

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/junit/GradleCompatibilitySuite.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -39,7 +39,7 @@ import org.springframework.boot.gradle.testkit.GradleBuild;
 public final class GradleCompatibilitySuite extends Suite {
 
 	private static final List<String> GRADLE_VERSIONS = Arrays.asList("default", "4.5.1",
-			"4.6", "4.7", "4.8.1", "4.9", "4.10.2", "5.0");
+			"4.6", "4.7", "4.8.1", "4.9", "4.10.3", "5.0", "5.1.1");
 
 	public GradleCompatibilitySuite(Class<?> clazz) throws InitializationError {
 		super(clazz, createRunners(clazz));

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/plugin/KotlinPluginActionIntegrationTests.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -43,12 +43,10 @@ public class KotlinPluginActionIntegrationTests {
 	}
 
 	@Test
-	public void kotlinVersionMatchesKotlinPluginVersion() {
+	public void kotlinVersionPropertyIsSet() {
 		String output = this.gradleBuild.build("kotlinVersion", "dependencies",
 				"--configuration", "compileClasspath").getOutput();
-		assertThat(output).contains("Kotlin version: 1.2.20");
-		assertThat(output)
-				.containsPattern("org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.2.20");
+		assertThat(output).containsPattern("Kotlin version: [0-9]\\.[0-9]\\.[0-9]+");
 	}
 
 	@Test

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/testkit/GradleBuild.java

 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2019 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.
@@ -195,7 +195,7 @@ public class GradleBuild implements TestRule {
 			gradleRunner.withGradleVersion(this.gradleVersion);
 		}
 		else if (this.dsl == Dsl.KOTLIN) {
-			gradleRunner.withGradleVersion("4.10.2");
+			gradleRunner.withGradleVersion("4.10.3");
 		}
 		List<String> allArguments = new ArrayList<>();
 		allArguments.add("-PbootVersion=" + getBootVersion());