diff --git a/conftest.py b/conftest.py
index 94d5cdd8b5..8dcf7e6805 100644
--- a/conftest.py
+++ b/conftest.py
@@ -37,6 +37,7 @@ def pytest_configure(config):
     'setuptools/_vendor',
     'pkg_resources/_vendor',
     'setuptools/config/_validate_pyproject',
+    'setuptools/modified.py',
 ]