Electron-Anleitung · 5/6

Testing

Dieses Kapitel ist vorerst nur auf Englisch verfügbar.

An Electron app has a main process, preload scripts, and renderers working together, so no single kind of test covers everything. This chapter shows how to unit test logic that does not depend on Electron, and how to write end-to-end (E2E) tests with Playwright that launch the real app and drive its windows.

A testing strategy

Kind	Target	Tools
Unit tests	Pure functions, data transforms, validation	Vitest, Jest
Module tests	Main process code that calls Electron APIs	Vitest with a mocked `electron`
Renderer component tests	React or Vue components	Your UI framework's testing tools
E2E tests	The whole running app	Playwright, WebdriverIO

The first step toward a testable app is to separate business logic from Electron APIs. Rather than writing long logic inside IPC handlers, extract it into pure functions and have the handlers simply call them.

Unit testing pure logic

Take a function that maintains a recent-files list. It knows nothing about Electron, so plain Node.js tests can check it.

// src/lib/recent-files.js
export function addRecentFile(list, file, max = 10) {
  return [file, ...list.filter((item) => item !== file)].slice(0, max)
}

npm install --save-dev vitest
npx vitest

// tests/recent-files.test.js
import { describe, it, expect } from 'vitest'
import { addRecentFile } from '../src/lib/recent-files'

describe('addRecentFile', () => {
  it('puts a new file first', () => {
    expect(addRecentFile(['a.txt'], 'b.txt')).toEqual(['b.txt', 'a.txt'])
  })

  it('moves an existing file to the front', () => {
    expect(addRecentFile(['a.txt', 'b.txt'], 'b.txt')).toEqual(['b.txt', 'a.txt'])
  })

  it('never exceeds the maximum length', () => {
    expect(addRecentFile(['a', 'b', 'c'], 'd', 3)).toEqual(['d', 'a', 'b'])
  })
})

Mocking the electron module

In plain Node.js, require('electron') returns the path to the Electron executable as a string, not the API. To load main process code in a Node.js test runner, replace the electron module with a mock.

// src/main/settings-path.js
import { app } from 'electron'
import path from 'node:path'

export const settingsPath = () => path.join(app.getPath('userData'), 'settings.json')

// tests/settings-path.test.ts
import { vi, it, expect } from 'vitest'
import path from 'node:path'

vi.mock('electron', () => ({
  app: { getPath: vi.fn(() => '/tmp/test-user-data') },
}))

import { settingsPath } from '../src/main/settings-path'

it('points at settings.json under userData', () => {
  expect(settingsPath()).toBe(path.join('/tmp/test-user-data', 'settings.json'))
})

Fragen zu diesem Kapitel?

Testing

A testing strategy

Unit testing pure logic

Mocking the electron module

End-to-end tests with Playwright

Running in CI

Summary

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