test: add additional npm specs

src/renderer/npm.ts

@@ -161,13 +161,13 @@ export function packageRun(
   return exec(dir, `${packageManager} run ${command}`);
 }
 
-function decommentWithWorker(input: string): Promise<string> {
+export function decommentWithWorker(input: string): Promise<string> {
   return new Promise((resolve, reject) => {
     const worker = new Worker('../utils/decomment.ts');
-    worker.postMessage(input);
     worker.onmessage = function (event: MessageEvent<string>) {
       resolve(event.data);
     };
+    worker.postMessage(input);
     worker.onerror = function (e) {
       reject(e);
     };

tests/mocks/worker.ts

@@ -0,0 +1,20 @@
+import * as decomment from 'decomment';
+
+export default class MockWorker {
+  public onmessage: (msg: any) => any;
+  public onmessageerror: () => any;
+  public onerror: () => any;
+  public addEventListener: () => any;
+  public removeEventListener: () => any;
+  public dispatchEvent: () => any;
+  public terminate: () => any;
+  constructor() {
+    this.onmessage = () => {
+      /*no-op*/
+    };
+  }
+
+  public postMessage(input: string) {
+    this.onmessage({ data: decomment(input) });
+  }
+}

tests/renderer/npm-spec.ts

@@ -1,23 +1,28 @@
+import { mocked } from 'ts-jest/utils';
+import * as decomment from 'decomment';
+
 import {
+  findModules,
   findModulesInEditors,
   getIsPackageManagerInstalled,
   installModules,
   packageRun,
 } from '../../src/renderer/npm';
 import { exec } from '../../src/utils/exec';
 import { overridePlatform, resetPlatform } from '../utils';
-
+import MockDecommentWorker from '../mocks/worker';
+jest.mock('decomment');
 jest.mock('../../src/utils/exec');
 jest.mock('../../src/utils/import', () => ({
   fancyImport: async (_p: string) => {
     return { default: require('builtin-modules') };
   },
 }));
 
-describe('npm', () => {
-  const mockMain = `
-    const say = require('say');
+window.Worker = MockDecommentWorker;
 
+describe('npm', () => {
+  const mockBuiltins = `
     function hello() {
       const electron = require('electron');
       const originalFs = require('original-fs');
@@ -26,6 +31,20 @@ describe('npm', () => {
     }
   `;
 
+  const mockPackages = `
+    const cow = require('cow');
+    const say = require('say');
+  `;
+
+  const mockComments = `
+    // const cow = require('cow');
+    /* const say = require('say'); */
+    /**
+     * const hello = require('hello'); 
+     * const world = require('world'); 
+    */
+  `;
+
   describe('getIsPackageManagerInstalled()', () => {
     describe('npm()', () => {
       beforeEach(() => {
@@ -150,17 +169,39 @@ describe('npm', () => {
     });
   });
 
+  describe('findModules()', () => {
+    it('returns required modules in a JS file', async () => {
+      mocked(decomment).mockReturnValue(mockPackages);
+      const modules = await findModules(mockPackages);
+      expect(modules).toEqual(['cow', 'say']);
+    });
+
+    it('ignores node and electron builtins', async () => {
+      mocked(decomment).mockReturnValue(mockBuiltins);
+      const modules = await findModules(mockBuiltins);
+      expect(modules).toHaveLength(0);
+    });
+
+    it('ignores commented modules', async () => {
+      mocked(decomment).mockReturnValue('');
+      const modules = await findModules(mockComments);
+      expect(modules).toHaveLength(0);
+    });
+  });
+
   describe('findModulesInEditors()', () => {
-    it('finds modules, ignoring node and electron builtins', async () => {
+    it('installs modules across all JavaScript files only once', async () => {
+      mocked(decomment).mockReturnValue(mockPackages);
       const result = await findModulesInEditors({
         html: '',
-        main: mockMain,
-        renderer: '',
-        preload: '',
+        main: mockPackages,
+        renderer: mockPackages,
+        preload: mockPackages,
         css: '',
       });
 
-      expect(result).toEqual(['say']);
+      expect(result).toHaveLength(2);
+      expect(result).toEqual(['cow', 'say']);
     });
   });