Jest Electron Runner

A custom test runner for Jest that runs tests inside an electron main or renderer process providing the following benefits:

• Main

  • all electron instance modules (ipc, app, etc)

• Renderer

  • full access to a browser environment without the need for jsdom or similar modules

This project is a fork of Facebook's @jest-runner/electron which seems to be no longer maintained, was archived on Github and is not working with newer Jest versions. I simplified the project, converted it from Flow to TypeScript and made it compatible to Jest 27 and newer.

Getting Started

1. Install jest electron runner with npm i --save-dev @kayahr/jest-electron-runner

2. Add one of these lines to your jest config (in package.json or inside your jest.config.js file), depending on the process you wish to test. If you wish to test them in parallel, see the tips section below.

   • Main process

     {
         "runner": "@kayahr/jest-electron-runner/main",
         "testEnvironment": "node"
     }

   • Renderer Process

     {
         "runner": "@kayahr/jest-electron-runner",
         "testEnvironment": "@kayahr/jest-electron-runner/environment"
     }

3. Run jest.

Configuration

jest-electron-runner can be configured through test environment options like this:

{
    "runner": "@kayahr/jest-electron-runner",
    "testEnvironment": "@kayahr/jest-electron-runner/environment",
    "testEnvironmentOptions": {
        "electron": {
            "options": [
                "no-sandbox",
                "ignore-certificate-errors",
                "force-device-scale-factor=1"
            ],
            "disableHardwareAcceleration": false
        }
    }
}

The test environment options shown in the above example are the default options. You can override these defaults as you like. If you want to remove a value-less electron option then prepend it with an exclamation mark (i.E. !ignore-certificate-errors).

The electron options can be any command-line option supported by Electron. The options can also be specified with the environment variable ELECTRON_OPTIONS.

Example:

ELECTRON_OPTIONS="--disable-webgl --enable-unsafe-webgpu"

Debugging

Normally jest-electron-runner runs a headless instance of electron when testing the renderer process. You may show the UI by adding this to your test:

// ES:
(await import("@electron/remote")).getCurrentWindow().show();

// CommonJS:
require("@electron/remote").getCurrentWindow().show();

Tips

• The main process runner can be used to test any non-browser related code, which can speed up tests roughly 2x.
• To run the main and renderer process tests in parallel, you can provide a config object to the projects array in the jest configuration:

  {
      "projects": [
          {
              "runner": "@kayahr/jest-electron-runner/main",
              "testEnvironment": "node"
          },
          {
              "runner": "@kayahr/jest-electron-runner",
              "testEnvironment": "@kayahr/jest-electron-runner/environment"
          }
      ]
  }

License

MIT licensed.