Extension Unit Tests

Peter Flynn edited this page Feb 20, 2015 · 5 revisions
Clone this wiki locally

Brackets includes a simple test-runner for internal use. You can leverage this same tool for any Brackets extensions you write (though not for other projects you're editing in Brackets... yet).

  1. Learn about the Jasmine unit-test framework.
  2. Make sure you are running Brackets from git source - the test-runner is not present in the regular download of Brackets. (And running from source is strongly recommended for extension developers anyway).
  3. Add a unittests.js module in the root of your extension folder.
  4. Write Jasmine test cases inside the module, using describe() {} blocks. Here's an example.
  5. Choose Debug > Run Tests
  6. Click the Extensions tab
  7. Click the name of your Jasmine block to run it

Example code


Start with the code from Simple "Hello World" extension. Then add exports.handleHelloWorld = handleHelloWorld; to the bottom of the module, inside the curly braces (this exposes the method as an API that unittests.js can invoke).


define(function (require, exports, module) {
    "use strict";

    var main = require("main");
    describe("Hello World", function () {
        it("should expose a handleHelloWorld method", function () {


This is not the easiest to use setup yet. Watch out for these gotchas:

  • You can open dev tools for the unit test window via its own "Show Developer Tools" button.
    • You must disable caching once you open dev tools -- even if you've already done so in the dev tools for the main Brackets window.
  • Your unit tests run in the test-runner window by default, so the Brackets UI DOM and certain Brackets modules won't be accessible. This may cause your code to fail.
  • You can run tests in a clean Brackets window using SpecRunnerUtils.createTestWindowAndRun(), which avoids the above problem. But this setup is not well documented and has its own pitfalls -- your test code needs to be careful about whether it's accessing something in the test-runner window vs. the popup Brackets window (for example, $ vs. testWindow.$). See ProjectManager-test for example code. Debugging tests inside these windows is also a bit tricky.