Add unit test

__tests__/setup-go.test.ts

@@ -3,7 +3,7 @@ import * as io from '@actions/io';
 import * as tc from '@actions/tool-cache';
 import fs from 'fs';
 import cp from 'child_process';
-import osm from 'os';
+import osm, {type} from 'os';
 import path from 'path';
 import * as main from '../src/main';
 import * as im from '../src/installer';
@@ -11,6 +11,7 @@ import * as im from '../src/installer';
 import goJsonData from './data/golang-dl.json';
 import matchers from '../matchers.json';
 import goTestManifest from './data/versions-manifest.json';
+import {addExecutablesToCache, IGoVersionInfo} from '../src/installer';
 const matcherPattern = matchers.problemMatcher[0].pattern[0];
 const matcherRegExp = new RegExp(matcherPattern.regexp);
 const win32Join = path.win32.join;
@@ -957,4 +958,39 @@ use .
       }
     );
   });
+
+  describe('Windows performance workaround', () => {
+    it('addExecutablesToCache should depends on env[RUNNER_TOOL_CACHE]', async () => {
+      const statSpy = jest.spyOn(fs, 'statSync');
+      // @ts-ignore
+      statSpy.mockImplementation(() => ({
+        isDirectory: () => true
+      }));
+      const readdirSpy = jest.spyOn(fs, 'readdirSync');
+      readdirSpy.mockImplementation(() => []);
+      const writeFileSpy = jest.spyOn(fs, 'writeFileSync');
+      writeFileSpy.mockImplementation(() => {});
+      const rmRFSpy = jest.spyOn(io, 'rmRF');
+      rmRFSpy.mockImplementation(() => Promise.resolve());
+      const mkdirPSpy = jest.spyOn(io, 'mkdirP');
+      mkdirPSpy.mockImplementation(() => Promise.resolve());
+      const cpSpy = jest.spyOn(io, 'cp');
+      cpSpy.mockImplementation(() => Promise.resolve());
+
+      const info: IGoVersionInfo = {
+        type: 'dist',
+        downloadUrl: 'http://nowhere.com',
+        resolvedVersion: '1.2.3',
+        fileName: 'ignore'
+      };
+
+      process.env['RUNNER_TOOL_CACHE'] = '/faked-hostedtoolcache1';
+      const cacheDir1 = await addExecutablesToCache('/qzx', info, 'arch');
+      expect(cacheDir1).toBe('/faked-hostedtoolcache1/go/1.2.3/arch');
+
+      process.env['RUNNER_TOOL_CACHE'] = '/faked-hostedtoolcache2';
+      const cacheDir2 = await addExecutablesToCache('/qzx', info, 'arch');
+      expect(cacheDir2).toBe('/faked-hostedtoolcache2/go/1.2.3/arch');
+    });
+  });
 });

src/installer.ts

@@ -164,7 +164,7 @@ async function resolveVersionFromManifest(
   }
 }
 
-async function addExecutablesToCache(
+export async function addExecutablesToCache(
   extPath: string,
   info: IGoVersionInfo,
   arch: string