reftests/bidi/729047-1.html and reftests/bugs/427730-1.html make assumptions about the combination of default font/fallback font not affecting the line-height. They need to set an explicit line-height to avoid this dependence. Both of these tests fail with Nightly running on WinXP ja-jp due to this problem.

While those particular tests could be fixed by setting an explicit line-height, I wonder if we could/should actually do something like the attached (untested) patch instead?

Hmm, not so simple, apparently. I tried pushing that to tryserver along with your patch from bug 739804, but those reftests still failed on XP with a line-height discrepancy.

I think this may be something to consider but could you push it to a separate bug? I'm going to try and go through and fix the tests where they contain font-related dependencies. There are a whole slew that fail when the locale is different (I usually test by running the reftest for the latest build then diffing with reftests run with a change).

I patched the two cases that were needed for bug 739804 to land but ran some separate tests, changing the default fonts on Windows to see what would happen. The reftests should not be dependent like this on default fonts, it causes differences for developers using machines with different default locales. Change default fonts to Georgia/Verdana: 51 failures on XP https://tbpl.mozilla.org/php/getParsedLog.php?id=12654391&tree=Try&full=1 54 failures on Win7 https://tbpl.mozilla.org/php/getParsedLog.php?id=12669385&tree=Try&full=1 60 failures on Win7/GDI https://tbpl.mozilla.org/php/getParsedLog.php?id=12668860&tree=Try&full=1 Change default fonts to Cambria/Calibri: 44 failures XP https://tbpl.mozilla.org/php/getParsedLog.php?id=12653900&tree=Try&full=1 58 failures on Win7 https://tbpl.mozilla.org/php/getParsedLog.php?id=12669535&tree=Try&full=1 58 failures on Win7/GDI https://tbpl.mozilla.org/php/getParsedLog.php?id=12667486&tree=Try&full=1 Change default fonts to Gabriola/Meiryo: 44 failures XP https://tbpl.mozilla.org/php/getParsedLog.php?id=12654381&tree=Try&full=1 101 failures on Win7 https://tbpl.mozilla.org/php/getParsedLog.php?id=12669921&tree=Try&full=1 106 failures on Win7/GDI https://tbpl.mozilla.org/php/getParsedLog.php?id=12669574&tree=Try&full=1 Depending on the underlying cause of the differences, there are several solutions: - explicitly declare lang="en" on the body - set the line height so that it's not dependent on font-height - rework the test so that it uses an explicit font list (e.g. Arial, sans-serif or whatever)