A XULRunner-Based Unit Test Harness


After finding a couple bugs in the Observers JS module recently, I looked around for a simple test harness to exercise it and other JS modules. Weave‘s (based on Mozilla’s xpcshell harness) seemed promising, although it has to hack around various limitations of xpcshell.

Atul Varma had suggested some time ago that a XULRunner-based harness might make sense, so I decided to see if I could modify Weave’s harness to run JS module tests using XULRunner instead of xpcshell.

Act 1

That proved doable, although some details were tricky. Sometimes I wondered whether I wouldn’t have been better off reusing MochiTest, although it’s heavier weight. Other times I wondered why I didn’t find this bug about XULRunner-based unit tests sooner, although it’s not clear that reusing the attachment in that bug would have been faster.

In any case, I got the harness working with XULRunner and wrote an initial set of tests of the Observers module. To run them, pull the jsmodules repository, change to its test/unit/ subdirectory, and run make with the location of your XULRunner executable (or set the XULRUNNER_BIN environment variable to its location):

hg clone https://hg.mozdev.org/jsmodules
cd jsmodules/test/unit/
make xulrunner_bin=/usr/bin/xulrunner

Since Firefox 3.0 comes with XULRunner, you can use any Firefox 3.0 (or newer) executable instead (except on Linux distros that ship Firefox as a XULRunner app–you have to use the XULRunner executable on those), like /Applications/Firefox.app/Contents/MacOS/firefox-bin on Mac and /c/Program Files/Mozilla Firefox/firefox.exe on Windows.


Once I got the harness working for jsmodules, I backported it to Weave, where it mostly works, except that IWeaveCrypto.generateKeypair (which calls PK11_GenerateKeyPair) fails, apparently because of SEC_ERROR_TOKEN_NOT_LOGGED_IN.

I have no idea why, but if you do, comment here or in bug 476539, since that’s the last blocker to Weave using this harness.


Myk Melez

Myk is a Principal Software Architect and in-house entrepreneur at Mozilla. A Mozillian since 1999, he's contributed to the Web App Developer Initiative, PluotSorbet, Open Web Apps, Firefox OS Simulator, Jetpack, Raindrop, Snowl, Personas, Firefox, Thunderbird, and Bugzilla. He's just a cook. He's all out of bubblegum.


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