Rewrite css21_dev/html4/{font-family,fonts}-013.htm to use a free font

[SimonSapin]

These tests rely on some fonts from Microsoft whose license does not allow redistribution. Getting these fonts on our CI servers is proving troublesome: #7625 (comment)

They should be modified to use different fonts whose license is not as problematic. To do so:

• Make sure the msttcorefonts package (or similar) is installed.
• Run ./mach test-css tests/wpt/css-tests/css21_dev/html4/fonts-013.htm tests/wpt/css-tests/css21_dev/html4/font-family-013.htm. The tests should pass.
• Uninstall the package.
• Run the tests again. They should fail.
• In the test files, replace "Times New Roman", "Arial", and "Courrier New" with serif, sans-serif, and monospace (without quotes) respectively.
• Run the tests again, with the package still uninstalled. Hopefully they should start passing.
• Run ./mach run tests/wpt/css-tests/css21_dev/html4/font-family-013.htm and ./mach run tests/wpt/css-tests/css21_dev/html4/fonts-013.htm Check that each file renders shows the word "Ţęşţ" (Test with some diacritics on each letter) six times, and not for example just a square for each letter or nothing at all.
• When everything looks good, submit a pull request to the upstream repository at https://github.com/w3c/csswg-test/tree/master/css21/fonts , not to the Servo repository. (Any local change to Servo’s copy of W3C tests would be overwritten at the next synchronization.)

[metajack]

Isn't this really a bug that should be filed upstream?

cc @Ms2ger @jgraham

[SimonSapin]

If the generic names serif, sans-serif or monspace don’t work, we’ll need to find some fonts that contain these characters and are available on all of our CI platforms.

[gsnedders]

@metajack yes, probably.

[SimonSapin]

I don’t know if this is really a bug upstream. When microsoft fonts are not available other browsers seem to pick other, similar fonts. The tests doesn’t really require non-free fonts, it’s just the easiest way we know to make it pass unmodified in our code. There’s probably more stuff we can improve in our font selection code.

(That said, if generic names work, there is no harm in making that change upstream too.)

[gsnedders]

Other browsers have magic to fallback for some super-common fonts. The test suite almost certainly shouldn't rely on non-free fonts or unspecified behaviour, IMO. I'm happy to champion (or help to) upstream (and I don't think there will be any disagreement).

[Ms2ger]

This change cannot be made here; it will be overwritten automatically.

[SimonSapin]

Good point, I’ve added a step to the instructions in the original message.

[0X1A]

Willing to take this issue

[SimonSapin]

@0X1A, great! Feel free to ask questions here or on IRC (#servo on irc.mozilla.org).

[0X1A]

@SimonSapin So, changing the fonts to their generic counterparts does not solve the tests and I get a fail for both.

Changing reference/font-family-013-ref.html to match the changes in html4/font-family-013.html gets the test to pass but font-013.htm still fails. Any suggestions? I'm guessing the ref's are upstream files?

[gsnedders]

@0X1A Do you have your changes anywhere?

[0X1A]

@gsnedders Yes, the changes are available here

[gsnedders]

That passes for me locally, FWIW. Oh, ignore me, I have the fonts so that's totally expected.

[gsnedders]

As I just commented in #7625 I'm leaning towards there being some bug in the font-matching code?

[frewsxcv]

As per #9697, the switch to generic fonts fails on Linux, but passes on OSX

[frewsxcv]

Nevermind, I guess it fails on OSX on the builders too, despite passing locally on my OSX machine.

[jdm]

Turns out this wasn't easy.