Add node's caching implementation (#2)

* first iteration for implementation of caching

* add logs

* add debug line

* fix build command

* fix path

* add possible post-if

* remove braces

* test new action post-if variant

* work on built-in caching

* remove post-if

* pass version

* work on yarn support

* fix return value

* change names and remove logs

* worked on resolving comments

* check post-if for null

* add success() condition

* remove primary key field

* work on resolving comments

* remove logs

* resolving comments

* resolving comments

* resolving comments

* resolving comments

* fix getpackageManagerVersion

* run clean for unstaged changes

* fix falling version tests

* work on resolving comments

* resolving comments

* fix comment

* resolve comments

* Add tests to cover node's caching (#3)

* add tests to cover node's caching

* work on fixing tests

* fix e2e tests

* rebuild and fix test

* fixing tests

* change name of describes, it and fix test

* add names for jobs

* fix issue

__tests__/cache-utils.test.ts

@@ -0,0 +1,52 @@
+import * as core from '@actions/core';
+import path from 'path';
+import * as utils from '../src/cache-utils';
+
+describe('cache-utils', () => {
+  const commonPath = '/some/random/path';
+  const versionYarn1 = '1.2.3';
+  const versionYarn2 = '2.3.4';
+
+  let debugSpy: jest.SpyInstance;
+  let getCommandOutputSpy: jest.SpyInstance;
+
+  function getPackagePath(name: string) {
+    if (name === utils.supportedPackageManagers.npm.getCacheFolderCommand) {
+      return `${commonPath}/npm`;
+    } else {
+      if (name === utils.supportedPackageManagers.yarn1.getCacheFolderCommand) {
+        return `${commonPath}/yarn1`;
+      } else {
+        return `${commonPath}/yarn2`;
+      }
+    }
+  }
+
+  beforeEach(() => {
+    process.env['GITHUB_WORKSPACE'] = path.join(__dirname, 'data');
+    debugSpy = jest.spyOn(core, 'debug');
+    debugSpy.mockImplementation(msg => {});
+
+    getCommandOutputSpy = jest.spyOn(utils, 'getCommandOutput');
+  });
+
+  describe('getPackageManagerInfo', () => {
+    it.each([
+      ['npm', utils.supportedPackageManagers.npm],
+      ['yarn', utils.supportedPackageManagers.yarn1],
+      ['yarn1', null],
+      ['yarn2', null],
+      ['npm7', null]
+    ])('getPackageManagerInfo for %s is %o', async (packageManager, result) => {
+      getCommandOutputSpy.mockImplementationOnce(() => versionYarn1);
+      await expect(utils.getPackageManagerInfo(packageManager)).resolves.toBe(
+        result
+      );
+    });
+  });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+    jest.clearAllMocks();
+  });
+});