Mock Native API in your E2E test

ElectronMeetup in Tokyo LT (https://connpass.com/event/69473/)

How to run spectron E2E test in case of using Native API in your specs.

Transcript

1. Mock Native API
   in your E2E test
   2017/11/06 ElectronMeetup in Tokyo LT
   @joe_re
   

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2. Who am I?
   twitter: @joe_re
   github: @joe­re
   community: Nishinippori.rb, GraphQL Tokyo Organizer
   

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3. Book
   

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4. Applications
   CafePitch
   Markdown Driven PresentationTool
   Tubutler
   Simple and usefull Youtube player
   

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5. Today, I talk about spectron E2E test
   in case of using 'Native API'
   in your spec.
   

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6. Spectron
   

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7. What is Spectron?
   E2E Testing tool for Electron appplication.
   You can call ElectronAPI in your spec via ChromeDriver and
   WebDriver.io.
   

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8. Example
   const app = new spectron.Application({ path: 'path/to/your/app' });
   describe('application launch', function () {
   this.timeout(10000);
   beforeEach(function () {
   return app.start();
   });
   afterEach(function () {
   return app.stop();
   });
   it('shows an initial window', function () {
   return app.client.getWindowCount().then(function (count) {
   assert.equal(count, 1);
   });
   });
   });
   

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9. Strong Points
   You can access any DOM via Webdriver.io.
   You can call any Electron API in your spec.
   No need setup script.(use Chromium inside Electron)
   Support CI services.(Travis, AppVeyor, etc)
   

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10. DEMO
    

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11. Spectron is nice.
    But it can't access Native API.
    (latest v3.7.2)
    So it can't mock Menu, Dialog, etc
    modules...
    https://github.com/electron/spectron/issues/94
    

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12. This is simple solution, but ugly...
    if (process.env.NODE_ENV === "production") {
    // production code here
    } else {
    // test code here
    }
    

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13. I want to write a spec which
    doesn't affect production code.
    

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14. I created two modules to resolve it.
    spectron­fake­menu
    https://github.com/joe­re/spectron­fake­menu
    spectron­fake­dialog
    https://github.com/joe­re/spectron­fake­dialog
    

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15. Usage
    spectron­fake­menu
    const Application = require('spectron').Application;
    const fakeMenu = require('spectron-fake-menu');
    const app = new Application({ path: electron, args: [ path.join(__dirname, '.') ] });
    fakeMenu.apply(app); // apply fake menu
    await app.start();
    fakeMenu.clickMenu('Config'); // 'Config' Menu click
    fakeMenu.clickMenu('File', 'CloseTab'); // File->CloseTab Menu click
    spectron­fake­dialog
    const Application = require('spectron').Application;
    const fakeDialog = require('spectron-fake-dialog');
    const app = new Application({ path: electron, args: [ path.join(__dirname, '.') ] });
    fakeDialog.apply(app);
    await app.start();
    fakeDialog.mock([ { method: 'showOpenDialog', value: ['faked.txt'] } ]));
    // write your specs
    

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16. How do they work?
    Electron provides '­­require' option same as Node.js.
    It can preload a module before run main script.
    These modules inject extra IPC and provide API which call
    or mock Native API inside your specs.
    

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17. Rough image
    

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18. Implementation(spectron­fake­dialog)
    const path = require('path');
    let _app = null;
    function apply(app) {
    _app = app;
    _app.args.unshift(path.join(__dirname, 'preload.js'));
    _app.args.unshift('--require');
    return _app;
    }
    function mock(options) {
    return _app.electron.ipcRenderer.sendSync('SPECTRON_FAKE_DIALOG/SEND', options);
    }
    module.exports = { apply, mock };
    

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19. Implementation(spectron­fake­dialog)
    preload script
    const { dialog, ipcMain, BrowserWindow } = require('electron');
    //... some logics for creating mocked function ...
    function fake(options) {
    options.forEach(v => {
    if (dialog[v.method]) {
    dialog[v.method] = mockFunction.bind(null, v.value);
    } else {
    throw new Error(`can't find ${v.method} on dialog module.`);
    }
    });
    }
    ipcMain.on('SPECTRON_FAKE_DIALOG/SEND', (e, options) => {
    fake(options);
    e.returnValue = true;
    });
    

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20. Please use they if you'd like.
    

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21. Thank you for your attention!
    

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