[Jasmine][jas] is an excellent framework for JavaScript testing, but I had a tough time coaxing it into cooperation with the Chrome extension I was developing. Jasmine's default testrunner uses an inline script block that listens for `window.onload` to setup the test environment, but Chrome prohibits extensions from running inline code. Alas, it's not as easy as importing the inline code as a separate file. After a little tinkering, this is what I came up with:

    Extension
        ├── html
        ├── js 
        ├── manifest.json
        └── tests
            ├── jasmine
            │   └── lib
            │       └── jasmine-1.2.0
            │           ├── MIT.LICENSE
            │           ├── jasmine-html.js
            │           ├── jasmine.css
            │           └── jasmine.js
            ├── loadjasmine.js
            ├── spec
            │   └── YourSpec.js
            └── tests.html

The `/jasmine/lib` directory includes the contents of the `lib` directory in Jasmine's [standalone release][standalone]. `tests.html` is a modified test runner and `loadjasmine.js` handles the setup. Put your specs in a `/tests/spec` directory, or wherever you want to find and import them. You can import the JavaScript code to test against directly from your `/js` directory or wherever you've put your background and content scripts.

The modified test runner includes a pair of buttons that set up the Jasmine environment and run the included specs. You might need to stub out some `chrome.*` methods, but this makes testing inside the extension as you develop much easier—which made me write more tests and run them more often. I added a link to my tests from my extension's options page so they were always at hand during development.

[jas]: http://pivotal.github.com/jasmine/
[standalone]: https://github.com/pivotal/jasmine/downloads