Skip on PyPy, seem to fail.

Author: Carreau

ipykernel/tests/test_kernel.py

@@ -425,6 +425,10 @@ def test_interrupt_with_message():
         validate_message(reply, 'execute_reply', msg_id)
 
 
+@pytest.mark.skipif(
+    "__pypy__" in sys.builtin_module_names,
+    reason="fails on pypy",
+)
 @pytest.mark.skipif(
     version.parse(IPython.__version__) < version.parse("7.14.0"),
     reason="Need new IPython"