Continuous Integration

Once you have your tests setup in your projects, you may want to automatically run them at any time a change is pushed by a developer. Continuous Integration's goal is to run these automated tests and even launch an automated build of your project.

Setting up CircleCI

CircleCI is a Continuous Integration service that is available for free. The way it works is quite simple and similar to most CI services: each time a commit is pushed to a branch in your git repository, CircleCI provisions a new, blank, machine. Your project is then cloned on it, installed and tests are run.

Open an account on CircleCI.

Go to https://circleci.com/ noob.

Add your project

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Enjoy the builds

CircleCI will try to infer most of the settings that you need. For projects using Node.js and npm, it will launch npm install and then run npm test.

Anytime you push a new commit/branch to your git repository, CircleCI will launch a new build. By default, you will be notified by mail if something went wrong.

Customize the settings with circle.yml

Most of the time, the settings inferred by CircleCI aren't adapted to your project. You may want to run a particular script before installing dependencies or install fixtures if you're testing a backend.

These settings can be added and changed in a configuration file called circle.yml, stored at the root of your repository.

Example 1: using a different Node version

If your project is using a particular version of Node, you can ask CircleCI to use it:

machine:
  node:
    version: 4.1.0

Example 2: Customize how your tests are run and reported

You can also change entire section of the build, and replace the way tests are run.

test:
  override:
    - MOCHA_FILE=$CIRCLE_TEST_REPORTS/unit.xml npm run test:unit -- --reporter mocha-junit-reporter

In this example, we're replacing the test run command by a new one that reports the result in a file. CircleCi exposes a few environment variables (like $CIRCLE_TEST_REPORTS here): the full list is in the CircleCI documentation.

Others services

CircleCI is only one of the many providers to offer Continuous Integration as a service. We chose it because it was easy to set up and free to try. You can also try Travis-CI which is free for open source projects.

In any case, be sure to read the docs if you're missing something.