diff --git a/tests/commands/test_mapping_sheet.py b/tests/commands/test_mapping_sheet.py
index 70d3978..adb27b9 100644
--- a/tests/commands/test_mapping_sheet.py
+++ b/tests/commands/test_mapping_sheet.py
@@ -1,9 +1,16 @@
+import platform
+
 import pytest
 
 from ocdskit.__main__ import main
 from tests import assert_command, assert_command_error, path
 
 
+# https://github.com/pypy/pypy/issues/4009
+@pytest.mark.skipif(
+    platform.system() == 'Darwin' and platform.python_implementation() == 'PyPy',
+    reason='CI outputs .../lib/pypy3.9/site-packages/certifi/cacert.pem None'
+)
 def test_command(capsys, monkeypatch):
     assert_command(capsys, monkeypatch, main,
                    ['mapping-sheet', '--infer-required', path('release-schema.json')],