test: require complete typecheck fixture coverage

tests/test_validate_typecheck_diagnostics.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+"""Regression tests for complete typecheck fixture coverage."""
+import importlib.util
+from pathlib import Path
+import unittest
+
+ROOT = Path(__file__).resolve().parents[1]
+SPEC = importlib.util.spec_from_file_location(
+    "validate_typecheck_diagnostics", ROOT / "tools" / "validate_typecheck_diagnostics.py"
+)
+MODULE = importlib.util.module_from_spec(SPEC)
+SPEC.loader.exec_module(MODULE)
+
+
+class ValidateTypecheckDiagnosticsTests(unittest.TestCase):
+    def test_lists_every_typecheck_fixture(self):
+        listed = set(MODULE.EXPECTED) | set(MODULE.EXPECTED_OK)
+        fixtures = {
+            str(path.relative_to(ROOT))
+            for path in (ROOT / "tests").glob("typecheck_*.claro")
+        }
+        fixtures.add("tests/37_object_field_types.claro")
+        self.assertEqual(listed, fixtures)
+
+
+if __name__ == "__main__":
+    unittest.main()