Apply Gradle Test Retry plugin

The plugin is configured to detect flaky tests and retry them 3 times
when running on the CI, but still reports failures. This will provide a
standard way to detect flaky tests as failures and successful attempts
are shown in the tests report.

build.gradle

@@ -46,7 +46,7 @@ configure([rootProject] + javaProjects) { project ->
 	apply plugin: "java"
 	apply plugin: "java-test-fixtures"
 	apply plugin: "checkstyle"
-	apply plugin: 'org.springframework.build.compile'
+	apply plugin: 'org.springframework.build.conventions'
 	apply from: "${rootDir}/gradle/toolchains.gradle"
 	apply from: "${rootDir}/gradle/ide.gradle"
 

buildSrc/README.md

@@ -5,9 +5,11 @@ They are declared in the `build.gradle` file in this folder.
 
 ## Build Conventions
 
-### Compiler conventions
+The `org.springframework.build.conventions` plugin applies all conventions to the Framework build:
+
+* Configuring the Java compiler, see `CompilerConventions`
+* Configuring testing in the build with `TestConventions` 
 
-The `org.springframework.build.compile` plugin applies the Java compiler conventions to the build.
 
 ## Build Plugins
 

buildSrc/build.gradle

@@ -9,6 +9,7 @@ repositories {
 
 dependencies {
 	implementation "me.champeau.gradle:japicmp-gradle-plugin:0.3.0"
+	implementation "org.gradle:test-retry-gradle-plugin:1.4.1"
 }
 
 gradlePlugin {
@@ -17,9 +18,9 @@ gradlePlugin {
 			id = "org.springframework.build.api-diff"
 			implementationClass = "org.springframework.build.api.ApiDiffPlugin"
 		}
-		compileConventionsPlugin {
+		conventionsPlugin {
-			id = "org.springframework.build.compile"
+			id = "org.springframework.build.conventions"
-			implementationClass = "org.springframework.build.compile.CompilerConventionsPlugin"
+			implementationClass = "org.springframework.build.ConventionsPlugin"
 		}
 		optionalDependenciesPlugin {
 			id = "org.springframework.build.optional-dependencies"

buildSrc/src/main/java/org/springframework/build/CompilerConventions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.build.compile;
+package org.springframework.build;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -22,6 +22,7 @@ import java.util.List;
 
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.api.plugins.JavaBasePlugin;
 import org.gradle.api.plugins.JavaLibraryPlugin;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.tasks.compile.JavaCompile;
@@ -33,7 +34,7 @@ import org.gradle.api.tasks.compile.JavaCompile;
  * @author Sam Brannen
  * @author Sebastien Deleuze
  */
-public class CompilerConventionsPlugin implements Plugin<Project> {
+public class CompilerConventions {
 
 	private static final List<String> COMPILER_ARGS;
 
@@ -58,9 +59,8 @@ public class CompilerConventionsPlugin implements Plugin<Project> {
 				"-Xlint:-deprecation", "-Xlint:-unchecked"));
 	}
 
-	@Override
 	public void apply(Project project) {
-		project.getPlugins().withType(JavaLibraryPlugin.class, javaPlugin -> applyJavaCompileConventions(project));
+		project.getPlugins().withType(JavaBasePlugin.class, javaPlugin -> applyJavaCompileConventions(project));
 	}
 
 	/**

buildSrc/src/main/java/org/springframework/build/ConventionsPlugin.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2002-2022 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.build;
+
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.plugins.JavaBasePlugin;
+
+/**
+ * Plugin to apply conventions to projects that are part of Spring Framework's build.
+ * Conventions are applied in response to various plugins being applied.
+ *
+ * When the {@link JavaBasePlugin} is applied, the conventions in {@link TestConventions}
+ * are applied.
+ * When the {@link JavaBasePlugin} is applied, the conventions in {@link CompilerConventions}
+ * are applied.
+ *
+ * @author Brian Clozel
+ */
+public class ConventionsPlugin implements Plugin<Project> {
+
+	@Override
+	public void apply(Project project) {
+		new TestConventions().apply(project);
+		new CompilerConventions().apply(project);
+	}
+}

buildSrc/src/main/java/org/springframework/build/TestConventions.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2002-2022 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.build;
+
+import org.gradle.api.Project;
+import org.gradle.api.plugins.JavaBasePlugin;
+import org.gradle.api.tasks.testing.Test;
+import org.gradle.testretry.TestRetryPlugin;
+import org.gradle.testretry.TestRetryTaskExtension;
+
+/**
+ * Conventions that are applied in the presence of the {@link JavaBasePlugin}. When the
+ * plugin is applied:
+ * <ul>
+ * <li>The {@link TestRetryPlugin Test Retry} plugins is applied so that flaky tests
+ * are retried 3 times when running on the CI.
+ * </ul>
+ *
+ * @author Brian Clozel
+ * @author Andy Wilkinson
+ */
+class TestConventions {
+
+	void apply(Project project) {
+		project.getPlugins().withType(JavaBasePlugin.class, (java) -> configureTestConventions(project));
+	}
+
+	private void configureTestConventions(Project project) {
+		project.getPlugins().apply(TestRetryPlugin.class);
+		project.getTasks().withType(Test.class,
+				(test) -> project.getPlugins().withType(TestRetryPlugin.class, (testRetryPlugin) -> {
+					TestRetryTaskExtension testRetry = test.getExtensions().getByType(TestRetryTaskExtension.class);
+					testRetry.getFailOnPassedAfterRetry().set(true);
+					testRetry.getMaxRetries().set(isCi() ? 3 : 0);
+				}));
+	}
+
+	private boolean isCi() {
+		return Boolean.parseBoolean(System.getenv("CI"));
+	}
+
+}

gradle/spring-module.gradle

@@ -1,5 +1,5 @@
 apply plugin: 'java-library'
-apply plugin: 'org.springframework.build.compile'
+apply plugin: 'org.springframework.build.conventions'
 apply plugin: 'org.springframework.build.optional-dependencies'
 // Uncomment the following for Shadow support in the jmhJar block.
 // Currently commented out due to ZipException: archive is not a ZIP archive