diff --git a/.github/workflows/unit_tests.yaml b/.github/workflows/unit_tests.yaml
index d3b127dc..e780c190 100644
--- a/.github/workflows/unit_tests.yaml
+++ b/.github/workflows/unit_tests.yaml
@@ -22,6 +22,10 @@ jobs:
         - name: Install Python packages
           run: pip3 install .[test]
 
+        - name: prepare input eta files
+          run: |
+            python tests/grid/generate_eta_files.py
+
         - name: Run serial-cpu tests
           run: coverage run --rcfile=setup.cfg -m pytest -x tests