fix: require the jsonschema format checkers

tests/test_audit_regressions.py

@@ -570,6 +570,26 @@ class PipelineRegressions(unittest.TestCase):
         self.assertTrue(full_models, truth_runs)
 
 
+class SchemaFormatsAreChecked(unittest.TestCase):
+    """date-time and uri need jsonschema's format extras; without them the
+    published format constraints were accepted unread."""
+
+    @unittest.skipUnless(HAS_JSONSCHEMA, "validating a schema needs jsonschema")
+    def test_a_missing_checker_is_named(self):
+        import validate_schemas
+
+        empty = mock.Mock(checkers={})
+        with mock.patch.object(validate_schemas, "FormatChecker", return_value=empty):
+            self.assertEqual(validate_schemas.unchecked_formats(), ["date-time", "uri"])
+
+    def test_every_install_asks_for_the_extras(self):
+        for path in (".github/workflows/validate.yml", ".github/workflows/deploy-site.yml",
+                     "pyproject.toml"):
+            text = (ROOT / path).read_text(encoding="utf-8")
+            with self.subTest(path=path):
+                self.assertNotRegex(text, r"jsonschema(?!\[format)[=>]")
+
+
 class ResolverRegressions(unittest.TestCase):
     def _database(self, entries: dict[str, Path], suffix: str | None = None) -> dict:
         files = {}

tests/test_check_freshness.py

@@ -318,5 +318,13 @@ class RepeatedDestinations(unittest.TestCase):
         self.assertEqual(diff.files_changed, ["pce/syscard3.pce"])
 
 
+class PinsWithExtras(unittest.TestCase):
+    def test_an_extras_bracket_keeps_its_pin(self):
+        from check_freshness import parse_pip_pins  # noqa: PLC0415
+
+        pins = parse_pip_pins('  run: pip install pyyaml "jsonschema[format-nongpl]==4.26.0"')
+        self.assertEqual(pins["jsonschema"], "==4.26.0")
+
+
 if __name__ == "__main__":
     unittest.main()