single test adjustment, because default parameter has changed

test/test_modules/test_experiment_setup.py

@@ -68,7 +68,7 @@ class TestExperimentSetup:
                             'DEBW052', 'DEBW034', 'DEBY088', ]
         assert data_store.get("stations", "general") == default_stations
         assert data_store.get("network", "general") == "AIRBASE"
-        assert data_store.get("station_type", "general") is None
+        assert data_store.get("station_type", "general") == "background"
         assert data_store.get("variables", "general") == list(default_statistics_per_var.keys())
         assert data_store.get("statistics_per_var", "general") == default_statistics_per_var
         assert data_store.get("start", "general") == "1997-01-01"