Further improve picamera tests to reuse fixtures and context managers.

hardware-specific-tests/picamera2/conftest.py

@@ -0,0 +1,33 @@
+"""Shared fixtures for picamera tests."""
+
+import pytest
+
+import labthings_fastapi as lt
+
+from openflexure_microscope_server.things.camera.picamera import StreamingPiCamera2
+
+from .cam_test_utils import camera_test_client
+
+
+@pytest.fixture
+def picamera_thing() -> StreamingPiCamera2:
+    """Return a StreamingPiCamera2 Thing.
+
+    This is the Thing that the fixture picamera_client uses. It can be used to probe
+    the Thing directly to check actions had the expected response.
+    """
+    return StreamingPiCamera2()
+
+
+@pytest.fixture
+def picamera_client(picamera_thing) -> lt.ThingClient:
+    """Initialise a test picamera_client for the StreamingPiCamera2 Thing.
+
+    This fixture:
+
+    * Sets up a ThingServer,
+    * Registers a StreamingPiCamera2 instance at the "/camera/" endpoint
+    * Provides a ThingClient for interacting with it during tests.
+    """
+    with camera_test_client(cam=picamera_thing) as picamera_client:
+        yield picamera_client