Patch provided upstream as https://github.com/nucleic/kiwi/pull/158
from issue created at https://github.com/nucleic/kiwi/issues/157

commit ad1c62f046dc14c1e85e4e1c1b8e175eda08838e
Author: Jérôme Carretero <cJ-kiwisolver@zougloub.eu>
Date:   Fri Feb 17 18:40:45 2023 -0500

    py: tests: make tests run under PyPy

diff --git a/py/tests/test_expression.py b/py/tests/test_expression.py
index 671dd7f..6b5d8e5 100644
--- a/py/tests/test_expression.py
+++ b/py/tests/test_expression.py
@@ -8,6 +8,7 @@
 import gc
 import math
 import operator
+import sys
 from typing import Tuple
 
 import pytest
@@ -264,4 +265,7 @@ def test_expression_rich_compare_operations(op, symbol) -> None:
     else:
         with pytest.raises(TypeError) as excinfo:
             op(e1, e2)
-        assert "kiwisolver.Expression" in excinfo.exconly()
+        if "PyPy" in sys.version:
+            assert "Expression" in excinfo.exconly()
+        else:
+            assert "kiwisolver.Expression" in excinfo.exconly()