Override freetype_rasterizer to make it mandatory for Google Fonts

At 8bf12c8, I noticed that it would be wise for the Google Fonts profile to also override the freetype_rasterizer check from SKIP (if freetype dependency is not installed) to a FAIL, just like Adobe Fonts does.

We will also need to setup the google/fonts CI rules so that we install freetype before running fontbakery on font PRs.

The check, on the Universal Profile, emits a SKIP by default because it is considered an optional check. But I think it should be mandatory for Google Fonts.
(issue #3871)

CHANGELOG.md

@@ -32,6 +32,7 @@ A more detailed list of changes is available in the corresponding milestones for
   - **[com.google.fonts/check/varfont_weight_instances]:** Removed due to new `fvar_instances` check (PR #3800)
   - **[com.google.fonts/check/varfont_instance_coordinates]:** Removed due to new `fvar_instances` check (PR #3800)
   - **[com.google.fonts/check/varfont_instance_names]:** Removed due to new `fvar_instances` check (PR #3800)
+  - **[com.adobe.fonts/check/freetype_rasterizer]:** Override this check to make it mandatory for Google Fonts, emitting a FAIL if freetype is not installed, instead of silently skipping. (issue #3871)
 
 ### BugFixes
   - **[com.google.fonts/check/unreachable_glyphs]:** Fix crash by adding support for color-font legacy COLR v0 format. (issue #3850)

Lib/fontbakery/profiles/googlefonts.py

@@ -4,8 +4,11 @@
 from fontbakery.status import INFO, WARN, ERROR, SKIP, PASS, FAIL
 from fontbakery.section import Section
 from fontbakery.callable import check, disable
-from fontbakery.utils import bullet_list, filesize_formatting, markdown_table
-from fontbakery.message import Message
+from fontbakery.utils import (add_check_overrides,
+                              bullet_list,
+                              filesize_formatting,
+                              markdown_table)
+from fontbakery.message import Message, KEEP_ORIGINAL_MESSAGE
 from fontbakery.fonts_profile import profile_factory
 from fontbakery.constants import (NameID,
                                   PlatformID,
@@ -29,6 +32,10 @@
     }
 }
 
+OVERRIDDEN_CHECKS = [
+    "com.adobe.fonts/check/freetype_rasterizer",
+]
+
 METADATA_CHECKS = [
     'com.google.fonts/check/metadata/parses',
     'com.google.fonts/check/metadata/unknown_designer',
@@ -6177,4 +6184,16 @@ def check_skip_filter(checkid, font=None, **iterargs):
 
 profile.check_skip_filter = check_skip_filter
 profile.auto_register(globals())
+
+profile.check_log_override(
+    # From universal.py
+    "com.adobe.fonts/check/freetype_rasterizer",
+    overrides=(("freetype-not-installed", FAIL, KEEP_ORIGINAL_MESSAGE),),
+    reason="For Google Fonts, this check is very important and should never be skipped.",
+)
+
+GOOGLEFONTS_PROFILE_CHECKS = add_check_overrides(
+    GOOGLEFONTS_PROFILE_CHECKS, profile.profile_tag, OVERRIDDEN_CHECKS
+)
+
 profile.test_expected_checks(GOOGLEFONTS_PROFILE_CHECKS, exclusive=True)

tests/profiles/googlefonts_test.py

@@ -1,6 +1,7 @@
 from fontbakery.profiles.googlefonts_conditions import expected_font_names
 import pytest
 import os
+from unittest.mock import patch
 from fontTools.ttLib import TTFont
 
 from fontbakery.checkrunner import (DEBUG, INFO, WARN, ERROR,
@@ -4197,3 +4198,18 @@ def test_check_STAT(fps, new_stat, result):
         assert_results_contain(check(ttFont, {"expected_font_names": expected}),
                                FAIL, 'bad-axis-values',
                                'with a bad font')
+
+
+OVERRIDE_SUFFIX = ":googlefonts"
+
+@patch("freetype.Face", side_effect=ImportError)
+def test_check_override_freetype_rasterizer(mock_import_error):
+    """Check that overridden test yields FAIL rather than SKIP."""
+    check = CheckTester(
+        googlefonts_profile,
+        f"com.adobe.fonts/check/freetype_rasterizer{OVERRIDE_SUFFIX}",
+    )
+
+    font = TEST_FILE("cabin/Cabin-Regular.ttf")
+    msg = assert_results_contain(check(font), FAIL, "freetype-not-installed")
+    assert "FreeType is not available" in msg