We cannot yet use PyTest

The name of the (single) test script doesn't adhere to `pytest` standards, so it is not found.
At the same time, there are a few Python files named "test*.py" that contain currently failing tests.
This needs to be fixed in a different PR.

.github/workflows/python.yml

@@ -23,4 +23,5 @@ jobs:
       - name: Install
         run: pip install .
       - name: Test
-        run: pytest -sv tools/losoto_test.py
+        # We cannot yet use `pytest`; requires different test file names
+        run: python tools/losoto_test.py