Further improve picamera tests to reuse fixtures and context managers.

hardware-specific-tests/picamera2/cam_test_utils/__init__.py

@@ -2,35 +2,40 @@
 
 from typing import Optional
 import tempfile
-
 from contextlib import contextmanager
 
 from fastapi.testclient import TestClient
 
-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
 
 
 @contextmanager
-def camera_test_client(settings_folder: Optional[str] = None):
+def camera_test_client(
+    cam: Optional[StreamingPiCamera2] = None, settings_folder: Optional[str] = None
+):
     """Yield a camera ThingClient on a camera server.
 
     This is a context manager not a pytest fixture as it needs to be created
     multiple times in some tests.
+
+    :param cam: The camera Thing to be used. If not supplied a new one will be created.
+    :param settings_folder: The settings folder for the camera, if none is supplies new
+        temporary directory will be used as the settings folder.
     """
+    if cam is None:
+        cam = StreamingPiCamera2()
     # Create a temp dir, if the setting folder is set it isn't really needed
     # but doesn't add much overhead.
     with tempfile.TemporaryDirectory() as tmpdir:
         if settings_folder is None:
             settings_folder = tmpdir
-        cam = StreamingPiCamera2()
-        server = ThingServer(settings_folder=settings_folder)
+        server = lt.ThingServer(settings_folder=settings_folder)
         server.add_thing(cam, "/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
     del server
     del cam