1-installation.md

Installing testdouble.js

Downloading testdouble.js

For use in Node.js (or Browserify)

To install and use in Node.js, simply install testdouble from npm:

$ npm install --save-dev testdouble

For ease-of-use, we recommend setting test double as a global throughout your test suite and to name that global something brief. We've been accustomed to using td, so in a test helper loaded before your tests:

global.td = require('testdouble')

All examples in these documents will assume testdouble is available as td.

For use in Browsers

The most recent release (not master itself) is always available on the master branch of the git repo, to make it easier to fetch the browser distribution of testdouble.js

curl

The easiest way to fetch testdouble is to curl it:

$ curl https://raw.githubusercontent.com/testdouble/testdouble.js/master/dist/testdouble.js -o test/helpers/testdouble.js

And then just check it into source control. It may be old-fashioned, but it still works.

npm

You can also install testdouble from npm and then copy, move, symlink, or point your front-end build tool at it:

$ npm install --save-dev testdouble

And then find the browser distribution of the library in node_modules/testdouble/dist/testdouble.js.

bower

To install testdouble.js with bower:

$ bower install --save-dev testdouble/testdouble.js

Once installed, the browser library can be found in bower_components/testdouble/dist/testdouble.js

Configuring testdouble.js Setting up in your test suite

testdouble.js is a standalone library. It can be used with any test library, such as QUnit, Mocha, Jasmine, or any other. In fact, you can use it without any test library at all.

Naming testdouble.js

Our browser distribution sets the library on a global variable named window.td. In Node.js, the library is loaded via require('testdouble'), as you might expect (though we recommend assigning it to global.td in a test helper, for terseness sake).

You're welcome to address testdouble.js or any of its functions however you prefer, but all of this documentation will assume that it's available globally as td.

Resetting state between test runs

The only configuration you'll want to make sure you set up is to reset the state of testdouble.js between tests, because it stores the state of all your test double functions globally. If you don't reset, you run the risk of succumbing to subtle test pollution and/or accidental order dependencies between tests.

For instance, Mocha and Jasmine both expose an afterEach method. In a top-level test helper, you could write:

afterEach(function(){
  td.reset()
})

In QUnit, you should be able to reset testdouble.js using the QUnit.testDone hook.

QUnit.testDone(function() {
  td.reset()
})