Add failing unit test as default tuning is updated during calibration

hardware-specific-tests/picamera2/test_acquisition.py

@@ -1,18 +1,29 @@
 """Test data collection from the Raspberry Picamera."""
 
+import tempfile
+
 from fastapi.testclient import TestClient
 from PIL import Image
 import numpy as np
 from pytest import fixture
 
-from labthings_fastapi.server import ThingServer
-from labthings_fastapi.client import ThingClient
+import labthings_fastapi as lt
 
 from openflexure_microscope_server.things.camera.picamera import StreamingPiCamera2
 
 
-@fixture(scope="module")
-def client():
+@fixture()
+def picamera_thing() -> StreamingPiCamera2:
+    """Return a StreamingPiCamera2 Thing.
+
+    This is the Thing that the fixture client uses. It can be used to probe the
+    Thing directly to check actions had the expected response.
+    """
+    return StreamingPiCamera2()
+
+
+@fixture()
+def client(picamera_thing) -> lt.ThingClient:
     """Initialise a test client for the StreamingPiCamera2 Thing.
 
     This fixture:
@@ -21,16 +32,23 @@ def client():
     * Registers a StreamingPiCamera2 instance at the "/camera/" endpoint
     * Provides a ThingClient for interacting with it during tests.
     """
-    server = ThingServer()
-    server.add_thing(StreamingPiCamera2(), "/camera/")
+    temp_folder = tempfile.TemporaryDirectory()
+    server = lt.ThingServer(settings_folder=temp_folder.name)
+    server.add_thing(picamera_thing, "/camera/")
     with TestClient(server.app) as test_client:
-        client = ThingClient.from_url("/camera/", client=test_client)
+        client = lt.ThingClient.from_url("/camera/", client=test_client)
         yield client
 
 
-def test_calibration(client):
+def test_calibration(picamera_thing, client):
     """Check that full auto calibrate completes without an exception."""
+    tuning = picamera_thing.tuning
+    default_tuning = picamera_thing.default_tuning
+    # Tuning should start the same as the server is loading with no settings.
+    assert default_tuning == tuning
+    # After calibration they should be different
     client.full_auto_calibrate()
+    assert default_tuning != tuning
 
 
 def test_jpeg_and_array(client):