CI: work around pytest+native namespace packages

.ci/unit_tests.sh

@@ -5,6 +5,10 @@ set -e
 pip install -r requirements.txt
 pip install -r requirements-dev.txt
 
+# pytest can have trouble with
+# native namespace packages
+export PYTHONPATH=$(pwd)
+
 # noroottest tests will fail/be skipped
 # if not executed as a non-root user, so
 # we run them as nobody