mocha-chai-boilerplate

Simple test boilerplate code. This repository can help bootstrap testing in a project.

The benefit of this boilerplate is that the test files automatically import their corresponding source files. This makes unit testing easy.

Using the template.txt

Inside your /test folder, create test files that match your /src structure. For example, your folder structure might look like the following, with each test-*.js file being a copy of template.txt.

/src
  /index.js
  /helpers
    /utils.js
    /strings.js
/test
  /test-index.js
  /helpers
    /test-utils.js
    /test-utils.async.js // See below
    /test-strings.js

Note that both test-utils.js and test-utils.async.js will run the code in test-utils.js. This helps split up large numbers of tests into multiple files.

Caveats

• Tests are in a folder named /test at the root of your project.
• Code are in a folder named /src at the root of your project.
• All test files begin with test-.
• All test files and source files end with .js.
• Code cannot be checked out to a path with /test in it. For example, if test-workspace is where your project lives, the test template won't work right.

Adding to a project

These steps will set up a test folder, and sets up your package.json in order to allow for testing with the following technologies:

• Mocha: Test framework
• Chai: Assertion library
• NYC: CLI for the Istanbul test runner, including enforcing coverage

This repository has examples of all the files you need to get set up below.

Get the dependencies

Inside your project, run the following:

> npm install chai mocha nyc --save-dev

Set up your test folder

Either copy the test folder from this package, or do the following:

• Create /test as a folder
• Inside it, create a mocha.opts file
• This file should contain --recursive as its contents
• Copy template.js to a file like test-index.js. Keep template.js around, for testing other files

Set up your npm test

Add this to your package.json under scripts:

// With linting, see below
"test": "nyc --check-coverage --lines 75  --functions 75 --branches 50 --reporter=html --reporter=text mocha --exit && npm run lint"

// Without linting
"test": "nyc --check-coverage --lines 75  --functions 75 --branches 50 --reporter=html --reporter=text mocha --exit"

You can change --lines, --functions, and --branches if you need higher or lower coverage.

Set up your .gitignore

Add the following lines to your .gitignore. If you don't have this file, add it to your repository:

.nyc_output
coverage

Linting

I like using ES Lint with AirBnB's style guide. It's very very good but not perfect, but many developers are familiar with it.

Get the dependencies

Inside your project, run the following:

> npx install-peerdeps --dev eslint-config-airbnb-base

Configure ES Lint

• Copy the .eslintrc file from this repository to your repository
• Add any custom rules here under the rules property

Set up npm run lint as a command

Add this to your package.json, under scripts:

  "lint": "./node_modules/.bin/eslint resources ./lib"

Testing

To ensure this repository works:

• npm install
• npm test

Should run tests and lint, with no errors.