Add support for testing the Gradle plugin with --configuration-cache

See gh-22922

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

@@ -41,4 +41,11 @@ import org.springframework.boot.gradle.testkit.GradleBuild;
 @ExtendWith(GradleCompatibilityExtension.class)
 public @interface GradleCompatibility {
 
+	/**
+	 * Whether to include running Gradle with {@code --cache-configuration} cache in the
+	 * compatibility matrix.
+	 * @return {@code true} to enable the configuration cache, {@code false} otherwise
+	 */
+	boolean configurationCache() default false;
+
 }

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

@@ -16,16 +16,19 @@
 
 package org.springframework.boot.gradle.junit;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Stream;
 
 import org.gradle.api.JavaVersion;
+import org.gradle.util.GradleVersion;
 import org.junit.jupiter.api.TestTemplate;
 import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
 import org.junit.jupiter.api.extension.TestTemplateInvocationContextProvider;
+import org.junit.platform.commons.util.AnnotationUtils;
 
 import org.springframework.boot.gradle.testkit.GradleBuild;
 import org.springframework.boot.gradle.testkit.GradleBuildExtension;
@@ -45,16 +48,29 @@ final class GradleCompatibilityExtension implements TestTemplateInvocationContex
 		JavaVersion javaVersion = JavaVersion.current();
 		if (javaVersion.isCompatibleWith(JavaVersion.VERSION_14)
 				|| javaVersion.isCompatibleWith(JavaVersion.VERSION_13)) {
-			GRADLE_VERSIONS = Arrays.asList("6.3", "6.4.1", "6.5.1", "6.6.1", "default");
+			GRADLE_VERSIONS = Arrays.asList("6.3", "6.4.1", "6.5.1", "6.6.1", "current");
 		}
 		else {
-			GRADLE_VERSIONS = Arrays.asList("5.6.4", "6.3", "6.4.1", "6.5.1", "6.6.1", "default");
+			GRADLE_VERSIONS = Arrays.asList("5.6.4", "6.3", "6.4.1", "6.5.1", "6.6.1", "current");
 		}
 	}
 
 	@Override
 	public Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context) {
-		return GRADLE_VERSIONS.stream().map(GradleVersionTestTemplateInvocationContext::new);
+		return GRADLE_VERSIONS.stream().flatMap((version) -> {
+			if (version.equals("current")) {
+				version = GradleVersion.current().getVersion();
+			}
+			List<TestTemplateInvocationContext> invocationContexts = new ArrayList<>();
+			invocationContexts.add(new GradleVersionTestTemplateInvocationContext(version, false));
+			boolean configurationCache = AnnotationUtils
+					.findAnnotation(context.getRequiredTestClass(), GradleCompatibility.class).get()
+					.configurationCache();
+			if (configurationCache && GradleVersion.version(version).compareTo(GradleVersion.version("6.6")) >= 0) {
+				invocationContexts.add(new GradleVersionTestTemplateInvocationContext(version, true));
+			}
+			return invocationContexts.stream();
+		});
 	}
 
 	@Override
@@ -66,20 +82,23 @@ final class GradleCompatibilityExtension implements TestTemplateInvocationContex
 
 		private final String gradleVersion;
 
-		GradleVersionTestTemplateInvocationContext(String gradleVersion) {
+		private final boolean configurationCache;
+
+		GradleVersionTestTemplateInvocationContext(String gradleVersion, boolean configurationCache) {
 			this.gradleVersion = gradleVersion;
+			this.configurationCache = configurationCache;
 		}
 
 		@Override
 		public String getDisplayName(int invocationIndex) {
-			return "Gradle " + this.gradleVersion;
+			return "Gradle " + this.gradleVersion + ((this.configurationCache) ? " --configuration-cache" : "");
 		}
 
 		@Override
 		public List<Extension> getAdditionalExtensions() {
-			GradleBuild gradleBuild = new GradleBuild();
-			if (!this.gradleVersion.equals("default")) {
-				gradleBuild.gradleVersion(this.gradleVersion);
+			GradleBuild gradleBuild = new GradleBuild().gradleVersion(this.gradleVersion);
+			if (this.configurationCache) {
+				gradleBuild.configurationCache();
 			}
 			return Arrays.asList(new GradleBuildFieldSetter(gradleBuild), new GradleBuildExtension());
 		}

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

@@ -72,6 +72,8 @@ public class GradleBuild {
 
 	private GradleVersion expectDeprecationWarnings;
 
+	private boolean configurationCache = false;
+
 	public GradleBuild() {
 		this(Dsl.GROOVY);
 	}
@@ -124,6 +126,11 @@ public class GradleBuild {
 		return this;
 	}
 
+	public GradleBuild configurationCache() {
+		this.configurationCache = true;
+		return this;
+	}
+
 	public BuildResult build(String... arguments) {
 		try {
 			BuildResult result = prepareRunner(arguments).build();
@@ -169,6 +176,9 @@ public class GradleBuild {
 		allArguments.addAll(Arrays.asList(arguments));
 		allArguments.add("--warning-mode");
 		allArguments.add("all");
+		if (this.configurationCache) {
+			allArguments.add("--configuration-cache");
+		}
 		return gradleRunner.withArguments(allArguments);
 	}