Actually, we set MOZ_BUNDLED_FONTS=1 on Windows and Linux. Since macOS doesn't set it, we cannot support Ahem font on web-platform-tests. (Windows has another bug as bug 1386496) Its font uses on some tests such as html/semantics/text-level-semantics/the-wbr-element/wbr-element.html, so we should set MOZ_BUNDLED_FONTS=1 on all platform.
As long as I know, font-display property's test on WPT also uses this font...
Yeah, it's generally assumed by wpt that Ahem is avaiable, so many tests depend on it. We either need to bundle the font with the browser (the approach we currently try), or ensure that it's installed into any machine image used in CI and hope local developers install it (or add it to mach bootstrap or so). The former seems preferable if it can work.
Jonathan, actually we doesn't pass a reftest of web-platform-tests since we don't set MOZ_BUNDLED_FONTS=1 on macOS. So, should we set MOZ_BUNDLED_FONTS=1 on all platform? Or, do you have other idea to detect external font on our test harness for web-platform-tests? (test harness copies Ahem.ttf to Resouces/res/fonts, not Resouces/fonts, so we don't detect Ahem.ttf even if set MOZ_BUNDLED_FONTS=1)
Note that bug 1336208 is also talking about "bundling" fonts (though providing them as downloadable content, rather than actually packaged with the browser as we currently do for the EmojiOne font). I don't know whether the intent there is to add the fonts to the installed browser itself, or to the user's profile.... but whatever is done there, can probably be used by the test harness for Ahem as well. > (test harness copies Ahem.ttf to Resouces/res/fonts, not Resouces/fonts, so > we don't detect Ahem.ttf even if set MOZ_BUNDLED_FONTS=1) That is presumably easy to fix, either by changing where the test harness puts it, or by changing the path that gfxMacPlatformFontList checks for bundled fonts. But I think we should coordinate this with bug 1336208; if they want to add fonts to the profile (rather than the app bundle), for example, then we could use that here as well.