# Automated tests
When working on a patch for DevTools, there's almost never a reason not to add a new test. If you are fixing a bug, you probably should write a new test to prevent this bug from occurring again. If you're implementing a new feature, you should write new tests to cover the aspects of this new feature.
* Are there enough tests for my patch?
* Are they the right types of tests?
We use three suites of tests:
* [Chrome mochitests](mochitest-chrome.md): Unit-test style of tests, but with a browser window. Mostly testing APIs that interact with the DOM.
* [DevTools mochitests](mochitest-devtools.md): Integration style of tests. Fires up a whole browser window with every test and you can test clicking on buttons, etc.
More information about the different types of tests can be found on the [automated testing page](https://developer.mozilla.org/en-US/docs/Mozilla/QA/Automated_testing) at MDN.
To run all DevTools tests, regardless of suite type:
./mach test devtools/*
Have a look at the child pages for more specific commands for running only a single suite or single test in a suite.