# Writing Tests There are several sources of GCLI tests and several environments in which they are run. The majority of GCLI tests are stored in [this repository](https://github.com/joewalker/gcli/) in files named like ```./lib/gclitest/test*.js```. These tests run in Firefox, Chrome, Opera, and NodeJS/JsDom See [Running Tests](running-tests.md) for further details. GCLI comes with a generic unit test harness (in ```./lib/test/```) and a set of helpers for creating GCLI tests (in ```./lib/gclitest/helpers.js```). # GCLI tests in Firefox The build process converts the GCLI tests to run under Mochitest inside the Firefox unit tests. It also adds some