neutrino-dev/docs/presets/neutrino-preset-karma

Neutrino Karma Preset

neutrino-preset-karma is a Neutrino preset that supports testing web applications using the Karma test runner.

Features

• Zero upfront configuration necessary to start testing on real browsers with Karma, Mocha, and Chrome
• Babel compilation that compiles your tests using the same Babel options used by your source code
• Source watching for re-running of tests on change
• Out-of-the-box support for running in CI
• Easily extensible to customize your testing as needed

Requirements

• Node.js v6.9+
• Yarn or npm client
• Neutrino v5, Neutrino build preset

Installation

neutrino-preset-karma can be installed via the Yarn or npm clients. Inside your project, make sure neutrino and neutrino-preset-karma are development dependencies. You will also be using another Neutrino preset for building your application source code.

Yarn

❯ yarn add --dev neutrino-preset-karma

npm

❯ npm install --save-dev neutrino-preset-karma

Project Layout

neutrino-preset-karma follows the standard project layout specified by Neutrino. This means that by default all project test code should live in a directory named test in the root of the project. Test files end in _test.js by default.

Quickstart

After adding the Karma preset to your Neutrino-built project, add a new directory named test in the root of the project, with a single JS file named simple_test.js in it.

❯ mkdir test && touch test/simple_test.js

Edit your test/simple_test.js file with the following:

import assert from 'assert';

describe('simple', () => {
  it('should be sane', () => {
    assert.equal(true, !false);
  });
});

Now edit your project's package.json to add commands for testing your application. In this example, let's pretend this is a React project:

{
  "scripts": {
    "test": "neutrino test --use neutrino-preset-react neutrino-preset-karma"
  }
}

Or if you have set up Neutrino with neutrino.use in your package.json:

{
  "neutrino": {
    "use": [
      "neutrino-preset-react",
      "neutrino-preset-karma"
    ]
  }
}

Run the tests, and view the results in your console:

Yarn

❯ yarn test

START:
16 02 2017 10:36:34.713:INFO [karma]: Karma v1.4.1 server started at http://0.0.0.0:9876/
16 02 2017 10:36:34.715:INFO [launcher]: Launching browser Chrome with unlimited concurrency
16 02 2017 10:36:34.731:INFO [launcher]: Starting browser Chrome
16 02 2017 10:36:35.655:INFO [Chrome 56.0.2924 (Mac OS X 10.12.3)]: Connected on socket MkTbqJLpAAa2HFaeAAAA with id 21326158
  simple
    ✔ should be sane

Finished in 0.003 secs / 0 secs @ 10:36:35 GMT-0600 (CST)

SUMMARY:
✔ 1 test completed
✨  Done in 7.54s.

npm

❯ npm test

START:
16 02 2017 10:38:12.865:INFO [karma]: Karma v1.4.1 server started at http://0.0.0.0:9876/
16 02 2017 10:38:12.867:INFO [launcher]: Launching browser Chrome with unlimited concurrency
16 02 2017 10:38:12.879:INFO [launcher]: Starting browser Chrome
16 02 2017 10:38:13.688:INFO [Chrome 56.0.2924 (Mac OS X 10.12.3)]: Connected on socket svRGoxU0etKTKQWhAAAA with id 68456725
  simple
    ✔ should be sane

Finished in 0.006 secs / 0 secs @ 10:38:13 GMT-0600 (CST)

SUMMARY:
✔ 1 test completed

To run tests against files from your source code, simply import them:

import thingToTest from '../src/thing';

For more details on specific Karma usage, please refer to their documentation.

Executing single tests

By default this preset will execute every test file located in your test directory ending in the appropriate file extension. Use the command line files parameters to execute individual tests.

Watching for changes

neutrino-preset-karma can watch for changes on your source directory and subsequently re-run tests. Simply use the --watch flag with your neutrino test command.

Using from CI

neutrino-preset-karma needs no additional configuration to run your tests in CI infrastructure, but you will still need to ensure your CI can actually run the tests. This usually means having a display emulator and access to the browsers you are testing against.

To do this in Travis-CI, you will need to add the following to your .travis.yml file for Chrome tests:

before_install:
  - export CHROME_BIN=chromium-browser
  - export DISPLAY=:99.0
  - sh -e /etc/init.d/xvfb start

Customizing

To override the test configuration, start with the documentation on customization. neutrino-preset-karma creates some conventions to make overriding the configuration easier once you are ready to make changes.

Simple customization

By following the customization guide you can override and augment the test configuration directly from package.json. neutrino-preset-karma will import Karma configuration from your package.json's neutrino.options.karma object if defined. The format is defined on the Karma documentation site.

Example: Change the duration Karma waits for a browser to reconnect (in ms).

{
  "neutrino": {
    "options": {
      "karma": {
        "browserDisconnectTimeout": 5000
      }
    }
  }
}

Advanced configuration

By following the customization guide you can override and augment testing by creating a JS module which overrides the config.

You can also modify Karma settings by overriding with any options Karma accepts. In a standalone Karma project this is typically done in a karma.conf.js file, but neutrino-preset-karma unifies advanced configuration through a preset override module. When needing to make changes to Karma-specific settings, this is stored in the neutrino.options.karma object, and takes the same configuration options as outlined in the Karma documentation.

Example: Change the duration Karma waits for a browser to reconnect (in ms).

module.exports = neutrino => {
  neutrino.options.karma.browserDisconnectTimeout = 5000;
};

Contributing

This preset is part of the neutrino-dev repository, a monorepo containing all resources for developing Neutrino and its core presets. Follow the contributing guide for details.