58 lines
1.9 KiB
Python
58 lines
1.9 KiB
Python
"""Use the Simulation camera to test base camera functionality."""
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import tempfile
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from contextlib import contextmanager
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import pytest
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from fastapi.testclient import TestClient
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import numpy as np
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from PIL import Image
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import labthings_fastapi as lt
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from openflexure_microscope_server.things.camera.simulation import SimulatedCamera
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@contextmanager
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def camera_server(camera: SimulatedCamera) -> lt.ThingClient:
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"""Add the camera to a ThingServer and start a TestClient application.
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The test client application is needed for the camera to have a blocking portal.
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"""
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with tempfile.TemporaryDirectory() as tmpdir:
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server = lt.ThingServer(settings_folder=tmpdir)
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server.add_thing(camera, "/camera/")
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with TestClient(server.app):
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yield server
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def test_handle_broken_frame():
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"""Monkey patch the the mjpeg steam so 1 in 5 frames are broken, then test operation.
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This simulates the very occasional broken frames that can occur when grabbing
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directly from the MJPEG stream.
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"""
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camera = SimulatedCamera()
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# Money patch the mjpeg_stream grab_frame to break 1 in 5 frames.
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frame_number = 0
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original_grabber = camera.mjpeg_stream.grab_frame
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async def flaky_grabber():
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"""Break 1 in 5 frames."""
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# Use a non-local variable to know the frame count.
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nonlocal frame_number
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frame = await original_grabber()
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if frame_number % 5 == 2:
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# Make a weird broken frame
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frame = frame[:2000] + frame[:2000]
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frame_number += 1
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return frame
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camera.mjpeg_stream.grab_frame = flaky_grabber
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with camera_server(camera):
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portal = lt.get_blocking_portal(camera)
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with pytest.raises(OSError, match="broken data stream when reading image file"):
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for _i in range(15):
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jpeg = camera.grab_jpeg(portal)
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np.asarray(Image.open(jpeg.open()))
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