diff --git a/.github/workflows/pythonpackage.yml b/.github/workflows/pythonpackage.yml
index 2844daba..be33d1d5 100644
--- a/.github/workflows/pythonpackage.yml
+++ b/.github/workflows/pythonpackage.yml
@@ -31,4 +31,5 @@ jobs:
     - name: Test with pytest
       run: |
         pip install pytest
+        pip install pytest-mock
         python -m pytest tests/