# Not Testing a Firefox Build (Generic Tasks in TaskCluster)

DevFeed: [Not Testing a Firefox Build (Generic Tasks in TaskCluster)](<https://devfeed.tech/articles/not-testing-a-firefox-build-generic-tasks-in-taskcluster-20302.md>)

Original publisher: [Read original article](<https://www.erranderr.com/blog/taskcluster-generic-tasks.html>)

Author: Maja Frydrychowicz

Published: 2016-05-02T04:00:00Z

Content type: article

Language: en

Sources: [Mozilla Automation](<https://devfeed.tech/sources/mozilla-automation.md>)

Topics: [Testing](<https://devfeed.tech/topics/testing.md>), [Script](<https://devfeed.tech/topics/script.md>), [Firefox](<https://devfeed.tech/topics/firefox.md>), [Mozilla](<https://devfeed.tech/topics/mozilla.md>)

Tags: [automation](<https://devfeed.tech/tags/automation.md>), [ci](<https://devfeed.tech/tags/ci.md>), [firefox](<https://devfeed.tech/tags/firefox.md>), [foss](<https://devfeed.tech/tags/foss.md>), [mozilla](<https://devfeed.tech/tags/mozilla.md>), [script](<https://devfeed.tech/tags/script.md>), [taskcluster](<https://devfeed.tech/tags/taskcluster.md>), [testing](<https://devfeed.tech/tags/testing.md>)

## AI overview

The article explains how Mozilla's generic TaskCluster tasks can run in-tree Marionette harness tests when files change, without waiting for a Firefox build or unrelated dependencies. It describes the chain of YAML configurations and shell scripts that checks out the source and runs mozharness, and explains why mozharness is preferred over a direct mach invocation for dependency and result handling.

## Source excerpt

I take advantage of generic tasks to run a mozharness script in a gecko source checkout.