diff --git a/run-tests.bat b/run-tests.bat
index 45028032..08b1646a 100644
--- a/run-tests.bat
+++ b/run-tests.bat
@@ -2,5 +2,6 @@ virtualenv .venv
 .venv\Scripts\pip install -e . --upgrade --upgrade-strategy=only-if-needed
 .venv\Scripts\pipenv install --dev
 
+SET PYPI_VENDOR_DIR '.\tests\pypi\'
 
 .venv\Scripts\pipenv run pytest -v tests -m "windows or cli" --tap-stream