| """Tests for harness/A/frames.py -- uniform/selective frame sampling.""" |
|
|
| import numpy as np |
| import pytest |
|
|
| from harness.A import frames as frame_sampling |
|
|
|
|
| def test_sample_frames_rejects_unknown_selection(tmp_path): |
| video = tmp_path / "scene.mp4" |
| video.write_bytes(b"not a real video") |
| with pytest.raises(ValueError): |
| frame_sampling.sample_frames(str(video), 8, "random") |
|
|
|
|
| def test_sample_frames_rejects_nonpositive_frame_count(tmp_path): |
| video = tmp_path / "scene.mp4" |
| video.write_bytes(b"not a real video") |
| with pytest.raises(ValueError): |
| frame_sampling.sample_frames(str(video), 0, "uniform") |
|
|
|
|
| def test_sample_frames_rejects_missing_video(tmp_path): |
| with pytest.raises(FileNotFoundError): |
| frame_sampling.sample_frames(str(tmp_path / "missing.mp4"), 8, "uniform") |
|
|
|
|
| def test_sample_frames_returns_pil_images_in_order(tmp_path, monkeypatch): |
| video = tmp_path / "scene.mp4" |
| video.write_bytes(b"not a real video") |
| fake_frames = np.stack( |
| [np.full((4, 4, 3), value, dtype=np.uint8) for value in (10, 20, 30)] |
| ) |
| monkeypatch.setattr( |
| frame_sampling, |
| "_sample_video_frames", |
| lambda path, count, selection: (fake_frames, np.array([0.0, 1.0, 2.0])), |
| ) |
|
|
| class _UnreadableCapture: |
| def get(self, prop): |
| return 0.0 |
|
|
| def release(self): |
| pass |
|
|
| monkeypatch.setattr( |
| frame_sampling.cv2, "VideoCapture", lambda path: _UnreadableCapture() |
| ) |
| result, timestamps, indices = frame_sampling.sample_frames(str(video), 3, "uniform") |
| assert len(result) == 3 |
| assert np.array(result[0])[0, 0, 0] == 10 |
| assert np.array(result[2])[0, 0, 0] == 30 |
| assert timestamps == [0.0, 1.0, 2.0] |
| |
| assert indices == [0, 1, 2] |
|
|
|
|
| def test_sample_frames_derives_indices_from_real_fps(tmp_path, monkeypatch): |
| video = tmp_path / "scene.mp4" |
| video.write_bytes(b"not a real video") |
| fake_frames = np.stack([np.full((2, 2, 3), 1, dtype=np.uint8)] * 3) |
| monkeypatch.setattr( |
| frame_sampling, |
| "_sample_video_frames", |
| lambda path, count, selection: (fake_frames, np.array([0.0, 0.5, 1.0])), |
| ) |
|
|
| class _FakeCapture: |
| def get(self, prop): |
| return 30.0 |
|
|
| def release(self): |
| pass |
|
|
| monkeypatch.setattr(frame_sampling.cv2, "VideoCapture", lambda path: _FakeCapture()) |
| _, timestamps, indices = frame_sampling.sample_frames(str(video), 3, "uniform") |
| assert timestamps == [0.0, 0.5, 1.0] |
| assert indices == [0, 15, 30] |
|
|
