test: cover standalone YESNO field checks

tests/test_validate_typecheck_diagnostics.py

@@ -28,6 +28,12 @@ class ValidateTypecheckDiagnosticsTests(unittest.TestCase):
             MODULE.EXPECTED_OK,
         )
 
+    def test_includes_dedicated_yesno_field_check_success_fixture(self):
+        self.assertIn(
+            "tests/typecheck_object_field_check_type_yesno_good.claro",
+            MODULE.EXPECTED_OK,
+        )
+
 
 if __name__ == "__main__":
     unittest.main()

tests/typecheck_object_field_check_type_yesno_good.claro

@@ -0,0 +1,7 @@
+CLASS Player
+    HAS ready YESNO
+END
+
+NEW Player player
+SET player.ready YES
+CHECK TYPE player.ready IS YESNO