Add experimental support for cache-cleanup

- Includes basic implementation as `CacheCleaner`
- Integration test that checks unused files are removed:
  - Downloaded dependencies
  - Local build cache entries
  - Wrapper distributions

test/jest/cache-cleanup.test.ts

@@ -0,0 +1,87 @@
+import * as exec from '@actions/exec'
+import fs from 'fs'
+import path from 'path'
+import {CacheCleaner} from '../../src/cache-cleaner'
+
+jest.setTimeout(120000)
+
+test('will cleanup unused dependency jars and build-cache entries', async () => {
+    const projectRoot = prepareTestProject()
+    const gradleUserHome = path.resolve(projectRoot, 'HOME')
+    const tmpDir = path.resolve(projectRoot, 'tmp')
+    const cacheCleaner = new CacheCleaner(gradleUserHome, tmpDir)
+
+    await runGradleBuild(projectRoot, 'build', '3.1')
+    
+    await cacheCleaner.prepare()
+
+    await runGradleBuild(projectRoot, 'build', '3.1.1')
+
+    const commonsMath31 = path.resolve(gradleUserHome, "caches/modules-2/files-2.1/org.apache.commons/commons-math3/3.1")
+    const commonsMath311 = path.resolve(gradleUserHome, "caches/modules-2/files-2.1/org.apache.commons/commons-math3/3.1.1")
+    const buildCacheDir = path.resolve(gradleUserHome, "caches/build-cache-1")
+
+    expect(fs.existsSync(commonsMath31)).toBe(true)
+    expect(fs.existsSync(commonsMath311)).toBe(true)
+    expect(fs.readdirSync(buildCacheDir).length).toBe(4)
+
+    await cacheCleaner.forceCleanup()
+
+    expect(fs.existsSync(commonsMath31)).toBe(false)
+    expect(fs.existsSync(commonsMath311)).toBe(true)
+    expect(fs.readdirSync(buildCacheDir).length).toBe(3)
+})
+
+test('will cleanup unused gradle versions', async () => {
+    const projectRoot = prepareTestProject()
+    const gradleUserHome = path.resolve(projectRoot, 'HOME')
+    const tmpDir = path.resolve(projectRoot, 'tmp')
+    const cacheCleaner = new CacheCleaner(gradleUserHome, tmpDir)
+
+    // Initialize HOME with 2 different Gradle versions
+    await runGradleWrapperBuild(projectRoot, 'build')
+    await runGradleBuild(projectRoot, 'build')
+    
+    await cacheCleaner.prepare()
+
+    // Run with only one of these versions
+    await runGradleBuild(projectRoot, 'build')
+
+    const gradle733 = path.resolve(gradleUserHome, "caches/7.3.3")
+    const wrapper733 = path.resolve(gradleUserHome, "wrapper/dists/gradle-7.3.3-bin")
+    const gradleCurrent = path.resolve(gradleUserHome, "caches/7.5.1")
+
+    expect(fs.existsSync(gradle733)).toBe(true)
+    expect(fs.existsSync(wrapper733)).toBe(true)
+    expect(fs.existsSync(gradleCurrent)).toBe(true)
+
+    await cacheCleaner.forceCleanup()
+
+    expect(fs.existsSync(gradle733)).toBe(false)
+    expect(fs.existsSync(wrapper733)).toBe(false)
+    expect(fs.existsSync(gradleCurrent)).toBe(true)
+})
+
+async function runGradleBuild(projectRoot: string, args: string, version: string = '3.1'): Promise<void> {
+    const status31 = await exec.exec(`gradle -g HOME --no-daemon --build-cache -Dcommons-math3.version=${version} ${args}`, [], {
+        cwd: projectRoot
+    })
+    console.log(`Gradle User Home initialized with commons-math3.version=${version} ${args}`)
+}
+
+async function runGradleWrapperBuild(projectRoot: string, args: string, version: string = '3.1'): Promise<void> {
+    const status31 = await exec.exec(`./gradlew -g HOME --no-daemon --build-cache -Dcommons-math3.version=${version} ${args}`, [], {
+        cwd: projectRoot
+    })
+    console.log(`Gradle User Home initialized with commons-math3.version=${version} ${args}`)
+}
+
+function prepareTestProject(): string {
+    const projectRoot = 'test/jest/resources/cache-cleanup'
+    fs.rmSync(path.resolve(projectRoot, 'HOME'), { recursive: true, force: true })
+    fs.rmSync(path.resolve(projectRoot, 'tmp'), { recursive: true, force: true })
+    fs.rmSync(path.resolve(projectRoot, 'build'), { recursive: true, force: true })
+    fs.rmSync(path.resolve(projectRoot, '.gradle'), { recursive: true, force: true })
+    return projectRoot
+}
+