Initial design for Build A/B testing epic story

src/main/groovy/org/mockito/release/internal/gradle/BuildABTestingPlugin.java

@@ -0,0 +1,190 @@
+package org.mockito.release.internal.gradle;
+
+import org.gradle.api.Action;
+import org.gradle.api.DefaultTask;
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.file.CopySpec;
+import org.gradle.api.tasks.*;
+import org.mockito.release.exec.DefaultProcessRunner;
+
+import java.io.File;
+
+/**
+ * See rationale and design at: https://github.com/mockito/mockito-release-tools/issues/113
+ */
+public class BuildABTestingPlugin implements Plugin<Project> {
+
+    public void apply(final Project project) {
+        //Step 1. Clone the repo for A/B testing
+        CloneGitHubRepositoryTask clone = project.getTasks().create("cloneGitHubRepository", CloneGitHubRepositoryTask.class);
+        clone.setRepository("mockito/mockito");
+        clone.setTargetDir(new File(project.getBuildDir(), "abTesting/mockito/pristine"));
+
+        //Step 2. Run A test
+        RunTestTask runA = project.getTasks().create("runA", RunTestTask.class);
+        runA.dependsOn(clone);
+        runA.setSourceDir(new File(clone.getTargetDir(),  "mockito"));
+        runA.setWorkDir(new File(project.getBuildDir(), "abTesting/mockito/testA-" + System.currentTimeMillis()));
+        runA.commandLine("./gradlew", "build");
+        runA.setOutputDir(new File(runA.getWorkDir(), "build"));
+
+        //Step 3. Run B test
+        RunTestTask runB = project.getTasks().create("runB", RunTestTask.class);
+        runB.dependsOn(clone);
+        runB.setSourceDir(new File(clone.getTargetDir(), "mockito"));
+        runB.setWorkDir(new File(project.getBuildDir(), "abTesting/mockito/testB-" + System.currentTimeMillis()));
+        runB.commandLine("./gradlew", "build");
+        runB.setOutputDir(new File(runB.getWorkDir(), "build"));
+
+        //Step 4. Compare test outcomes
+        CompareDirectoriesTask compare = project.getTasks().create("compareAB", CompareDirectoriesTask.class);
+        compare.dependsOn(runA, runB);
+        compare.setDirA(runA.getOutputDir());
+        compare.setDirB(runB.getOutputDir());
+        compare.setResultsFile(new File(project.getBuildDir(), "abTesting/mockito/results.ser")); //or JSON :)
+
+        //Step 5. Analyze comparison results
+        AnalyzeComparisonResultsTask analyze = project.getTasks().create("analyzeAB", AnalyzeComparisonResultsTask.class);
+        analyze.dependsOn(compare);
+        analyze.setComparisonResultsFile(compare.getResultsFile());
+    }
+
+    /**
+     * BELOW task types are only empty shells.
+     * They act as suggestions for workflow / API design.
+     */
+
+    public static class AnalyzeComparisonResultsTask extends DefaultTask {
+
+        private File comparisonResultsFile;
+
+        @InputFile
+        public void setComparisonResultsFile(File comparisonResultsFile) {
+            this.comparisonResultsFile = comparisonResultsFile;
+        }
+    }
+
+    public static class CompareDirectoriesTask extends DefaultTask {
+
+        private File dirA;
+        private File dirB;
+        private File resultsFile;
+
+        @InputDirectory
+        public void setDirA(File dir) {
+            this.dirA = dir;
+        }
+
+        @InputDirectory
+        public void setDirB(File dir) {
+            this.dirB = dir;
+        }
+
+        public void setResultsFile(File file) {
+            this.resultsFile = file;
+        }
+
+        @OutputFile
+        public File getResultsFile() {
+            return resultsFile;
+        }
+    }
+
+    public static class RunTestTask extends DefaultTask {
+
+        private File sourceDir;
+        private File workDir;
+        private File outputDir;
+        private String[] arg;
+
+        @InputDirectory
+        public void setSourceDir(File sourceDir) {
+            this.sourceDir = sourceDir;
+        }
+
+        public void setWorkDir(File workDir) {
+            this.workDir = workDir;
+        }
+
+        @Input
+        public void commandLine(String ... arg) {
+            this.arg = arg;
+        }
+
+        public File getWorkDir() {
+            return workDir;
+        }
+
+        public void setOutputDir(File outputDir) {
+            this.outputDir = outputDir;
+        }
+
+        @OutputDirectory
+        public File getOutputDir() {
+            return outputDir;
+        }
+
+        @TaskAction
+        public void executeTestTask() {
+            if (outputDir != null && !outputDir.exists()) {
+                outputDir.mkdirs();
+            }
+            getProject().copy(new Action<CopySpec>() {
+                public void execute(CopySpec copy) {
+                    copy.from(sourceDir).into(workDir);
+                }
+            });
+            new DefaultProcessRunner(workDir).run(arg);
+        }
+    }
+
+    public static class CompareABTask extends DefaultTask {
+    }
+
+    public static class CloneGitHubRepositoryTask extends DefaultTask {
+
+        private String repository;
+        private File targetDir;
+        private static final String REPO_BASE_URL = "https://github.com/";
+
+        @Input
+        public void setRepository(String repository) {
+            this.repository = repository;
+        }
+
+        public void setTargetDir(File targetDir) {
+            this.targetDir = targetDir;
+        }
+
+        @OutputDirectory
+        public File getTargetDir() {
+            return targetDir;
+        }
+
+        @TaskAction
+        public void cloneGit() {
+            if(targetDir != null && !targetDir.exists()) {
+                targetDir.mkdirs();
+            }
+
+            if (repository == null || repository.isEmpty()) {
+                throw new RuntimeException("Invalid repository '" + repository + "' given!");
+            }
+
+            String url = REPO_BASE_URL + repository;
+
+            new DefaultProcessRunner(targetDir).run("git", "clone", url);
+        }
+    }
+
+    public static class PrepareABTestingTask extends DefaultTask {
+
+        private File sourceDir;
+
+        @InputDirectory
+        public void setSourceDir(File sourceDir) {
+            this.sourceDir = sourceDir;
+        }
+    }
+}

src/main/resources/META-INF/gradle-plugins/org.mockito.mockito-release-tools.build-ab-testing.properties

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+implementation-class=org.mockito.release.internal.gradle.BuildABTestingPlugin

src/test/groovy/org/mockito/release/internal/gradle/BuildABTestingPluginTest.groovy

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+package org.mockito.release.internal.gradle
+
+import org.gradle.testfixtures.ProjectBuilder
+import spock.lang.Specification
+
+class BuildABTestingPluginTest extends Specification {
+
+    def project = new ProjectBuilder().build()
+
+    def "applies"() {
+        expect:
+        project.plugins.apply(BuildABTestingPlugin.class);
+    }
+}