Update testenvs with minimal app config

Worked out by Beth Probert

tests/unit_tests/test_base_camera.py

@@ -5,6 +5,8 @@ test_simulated_camera.py and for testing the consistency of camera APIs see
 test_cameras.py.
 """
 
+import tempfile
+
 import numpy as np
 import pytest
 from PIL import Image
@@ -19,7 +21,8 @@ from ..shared_utils.lt_test_utils import LabThingsTestEnv
 def test_env() -> LabThingsTestEnv:
     """Yield a test environment with the Simulated Camera and Dummy Stage."""
     thing_conf = {"camera": SimulatedCamera, "stage": DummyStage}
-    with LabThingsTestEnv(things=thing_conf) as env:
+    app_config = {"data_folder": tempfile.gettempdir()}
+    with LabThingsTestEnv(things=thing_conf, application_config=app_config) as env:
         yield env