Automated Firefox tests with add-ons installed

Mozmill has a feature that allows the tester to install an add-on during the test run. Until recently this was only used by one of our automated testruns, which was for specifically testing the installed add-on rather than Firefox.

With the recent development on the endurance tests project, it has been necessary to take more advantage of this feature. A bug was reported where if Adblock Plus – our most popular add-on – is installed memory usage increased rapidly when navigating a web page, and none of the memory was being released. To start investigating this I created a very basic (and specific) test for the site mentioned in the bug report, and then simply hacked something together based on the existing add-ons test run. A short time later, the need to run the endurance tests with multiple add-ons installed came up, so I hacked some more to get that in place too. Rather than keep these hacks around, it made sense to allow testers to specify add-ons to be installed during any of our testruns, so I started to work on the necessary patches.

As a result, testers can now run any of our automation scripts with one or more add-ons installed by simply specifying the addons command line parameter. To install multiple add-ons simply repeat the parameter. The argument can either be a path on your machine, or a web/ftp server. In the latter case the add-on will be downloaded to a temporary location before the testrun and removed at the end. The latest version of Mozmill (1.5.2) also now disables the compatibility check, meaning that we can run tests with add-ons that are not marked as compatible with the version of Firefox in use.

An example of running the endurance tests with two add-ons installed:

./ --addons= --addons=/Users/dave/Downloads/noscript.xpi --delay=1000 --iterations=10 /Applications/

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