Run your Atom package tests using Mocha
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Atom Mocha Test Runner

By default, Atom runs your tests with Jasmine (for more information on testing packages in Atom, please see the Atom Flight Manual). Atom allows you to specify a custom test runner using the atomTestRunner field in your package.json, but implementing a custom test runner is not straightforward. This module allows you to run your specs using Mocha with minimal fuss.


$ apm install [--save-dev] atom-mocha-test-runner


Default Test Runner

If you want to use all the default options, simply pass the module name as the atomTestRunner value in your package.json:

  "name": "my-package",
  // ...
  "atomTestRunner": "atom-mocha-test-runner"

Note that your package.json may be cached by Atom's compile cache when running tests with Atom's GUI test runner, so if adding or changing that field doesn't seem to work, try quitting and restarting Atom.

Programmatic Usage

If you'd like to perform more customization of your testing environment, you can create a custom runner while still utilizing atom-mocha-test-runner for most of the heavy lifting. First, set atomTestRunner to a relative path to a file:

  "name": "my-package",
  // ...
  "atomTestRunner": "./test/custom-runner"

Then export a test runner created via the atom-mocha-test-runner from test/custom-runner.js:

var createRunner = require('atom-mocha-test-runner').createRunner

// optional options to customize the runner
var extraOptions = {
  testSuffixes: ['-spec.js', '']

var optionalConfigurationFunction = function (mocha) {
  // If provided, atom-mocha-test-runner will pass the mocha instance
  // to this function, so you can do whatever you'd like to it.

module.exports = createRunner(extraOptions, optionalConfigurationFunction)


createRunner([options,] [callback])

Returns a test runner created with the given options and callback. Both parameters are optional. The returned value can be exported from your atomTestRunner script for Atom to consume.

  • options - An object specifying customized options:

    • options.reporter [default: 'dot'] - Which reporter to use on the terminal
    • globalAtom [default: true] - Whether or not to assign the created Atom environment to global.atom
    • testSuffixes [default: ['test.js', '']] - File extensions that indicate that the file contains tests
    • colors [default: true] - Whether or not to colorize output on the terminal
    • htmlTitle [default: ''] - The string to use for the window title in the HTML reporter

Making Assertions

atom-mocha-test-runner does not include any assertion libraries; it only includes the Mocha test runner. You can pull in any assertion library you want, but Chai is a great choice.

const assert = require('chai').assert

describe('Testing', function () {
  it('works', function () {
    assert.equal(answerToLifeUniverseAndEverything, 42)