Skip param groupings test if doesnt exist

pysr/test/test.py

@@ -770,6 +770,9 @@ class TestMiscellaneous(unittest.TestCase):
     def test_param_groupings(self):
         """Test that param_groupings are complete"""
         param_groupings_file = Path(__file__).parent.parent / "param_groupings.yml"
+        if not param_groupings_file.exists():
+            return
+
         # Read the file, discarding lines ending in ":",
         # and removing leading "\s*-\s*":
         params = []