如何使用 jest 测试 electro ipc 事件？

Question

我正在对我正在构建的电子应用程序进行一些测试。我遇到了下面的错误。我是开玩笑的新手，所以我想这是由于设置不正确造成的。知道我哪里出错了吗？

Error: Cannot find module 'ipcMain' from 'ipcMainEvents.spec.js'

//myEvents.ts

import { ipcMain } from 'electron'

export class IpcMainEvents {

    constructor() {
        ipcMain.on('openPlaywright', this.openPlaywright)
        ipcMain.on('openPreviewBrowser', this.openPlaywright)
    }


    openPlaywright(event, arg) {
        console.log('openPlaywright')
    }

    openPreviewBrowser(event, arg) {
        console.log('openPreviewBrowser')
    }
}

//myEvents.spec.ts

import {IpcMainEvents} from './ipcMainEvents'
import {ipcMain} from 'electron'
jest.mock('ipcMain')


describe('Should test the ipcMain events', () => {
    let component;
    let addSpy
    beforeEach(()=>{
        component = new IpcMainEvents()

    }) 
    it('should attach the eventListeners', () => { 

        expect(component.ipcMain.on.calls.all()[0].args[0]).toEqual('openPlaywright'); //<----Errors here
        expect(component.ipcMain.on.calls.all()[1].args[0]).toEqual('openPreviewBrowser');
        expect(component.ipcMain.on.calls.count()).toEqual(2);
    });

});

Answer 1

首先，您应该模拟electron包，而不是ipcMain函数。

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其次，您应该通过.mock propertycalls访问模拟函数的属性。

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例如

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myEvents.ts：

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import { ipcMain } from \'electron\';\n\nexport class IpcMainEvents {\n  constructor() {\n    ipcMain.on(\'openPlaywright\', this.openPlaywright);\n    ipcMain.on(\'openPreviewBrowser\', this.openPlaywright);\n  }\n\n  openPlaywright(event, arg) {\n    console.log(\'openPlaywright\');\n  }\n\n  openPreviewBrowser(event, arg) {\n    console.log(\'openPreviewBrowser\');\n  }\n}\n

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myEvents.spec.ts：

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import { IpcMainEvents } from \'./myEvents\';\nimport { ipcMain } from \'electron\';\n\njest.mock(\n  \'electron\',\n  () => {\n    const mockIpcMain = {\n      on: jest.fn().mockReturnThis(),\n    };\n    return { ipcMain: mockIpcMain };\n  },\n  { virtual: true },\n);\n\ndescribe(\'Should test the ipcMain events\', () => {\n  let component;\n  let addSpy;\n  beforeEach(() => {\n    component = new IpcMainEvents();\n  });\n  it(\'should attach the eventListeners\', () => {\n    expect(ipcMain.on.mock.calls[0][0]).toEqual(\'openPlaywright\');\n    expect(ipcMain.on.mock.calls[1][0]).toEqual(\'openPreviewBrowser\');\n    expect(ipcMain.on.mock.calls).toHaveLength(2);\n  });\n});\n

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带有覆盖率报告的单元测试结果：

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 PASS  stackoverflow/61562193/myEvents.spec.js (10.657s)\n  Should test the ipcMain events\n    \xe2\x9c\x93 should attach the eventListeners (3ms)\n\n-------------|---------|----------|---------|---------|-------------------\nFile         | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s \n-------------|---------|----------|---------|---------|-------------------\nAll files    |      80 |      100 |      50 |   77.78 |                   \n myEvents.js |      80 |      100 |      50 |   77.78 | 10,14             \n-------------|---------|----------|---------|---------|-------------------\nTest Suites: 1 passed, 1 total\nTests:       1 passed, 1 total\nSnapshots:   0 total\nTime:        11.917s\n

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