Initial project import

tests/test_deep_scan.py

@@ -0,0 +1,140 @@
+"""
+tests/test_deep_scan.py — Unit tests for frame_extractor and deep_scan
+
+Uses synthetic in-memory videos (cv2.VideoWriter → temp file) so no real
+video files are required. Tests cover the pure logic, not hardware decoding.
+"""
+
+from __future__ import annotations
+
+import tempfile
+from pathlib import Path
+
+import cv2
+import numpy as np
+import pytest
+
+from src.cv.frame_extractor import (
+    get_video_info,
+    grab_frame_at,
+    iter_frames_stepped,
+    open_video,
+)
+from src.cv.fingerprinting import text_safe_crop
+
+
+# ---------------------------------------------------------------------------
+# Helpers: build a tiny synthetic video on disk
+# ---------------------------------------------------------------------------
+
+FPS    = 24
+WIDTH  = 320
+HEIGHT = 240
+SECS   = 3
+
+
+def _make_synthetic_video(path: Path, color_bgr: tuple[int, int, int] = (0, 128, 255)) -> Path:
+    """Write a 3-second single-colour video to *path*."""
+    fourcc = cv2.VideoWriter_fourcc(*"mp4v")
+    writer = cv2.VideoWriter(str(path), fourcc, float(FPS), (WIDTH, HEIGHT))
+    frame  = np.full((HEIGHT, WIDTH, 3), color_bgr, dtype=np.uint8)
+    for _ in range(FPS * SECS):
+        writer.write(frame)
+    writer.release()
+    return path
+
+
+@pytest.fixture
+def synthetic_video(tmp_path: Path) -> Path:
+    return _make_synthetic_video(tmp_path / "test.mp4")
+
+
+# ---------------------------------------------------------------------------
+# open_video
+# ---------------------------------------------------------------------------
+
+class TestOpenVideo:
+    def test_opens_valid_file(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            assert cap.isOpened()
+
+    def test_raises_on_missing_file(self, tmp_path: Path) -> None:
+        with pytest.raises(FileNotFoundError):
+            with open_video(tmp_path / "ghost.mp4"):
+                pass
+
+
+# ---------------------------------------------------------------------------
+# get_video_info
+# ---------------------------------------------------------------------------
+
+class TestGetVideoInfo:
+    def test_returns_correct_fps(self, synthetic_video: Path) -> None:
+        info = get_video_info(synthetic_video)
+        assert info["fps"] == pytest.approx(FPS, rel=0.05)
+
+    def test_duration_approx(self, synthetic_video: Path) -> None:
+        info = get_video_info(synthetic_video)
+        assert info["duration_s"] == pytest.approx(SECS, rel=0.1)
+
+    def test_resolution(self, synthetic_video: Path) -> None:
+        info = get_video_info(synthetic_video)
+        assert info["width"]  == WIDTH
+        assert info["height"] == HEIGHT
+
+
+# ---------------------------------------------------------------------------
+# grab_frame_at
+# ---------------------------------------------------------------------------
+
+class TestGrabFrameAt:
+    def test_returns_ndarray(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            frame = grab_frame_at(cap, 1.0)
+        assert frame is not None
+        assert isinstance(frame, np.ndarray)
+        assert frame.shape == (HEIGHT, WIDTH, 3)
+
+    def test_returns_none_past_end(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            frame = grab_frame_at(cap, 9999.0)
+        # May return None or a repeated last frame depending on codec;
+        # we only assert no exception is raised.
+        assert frame is None or isinstance(frame, np.ndarray)
+
+
+# ---------------------------------------------------------------------------
+# iter_frames_stepped
+# ---------------------------------------------------------------------------
+
+class TestIterFramesStepped:
+    def test_yields_correct_count(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            frames = list(iter_frames_stepped(cap, 0.0, 1.0, 0.5))
+        # Expect timestamps: 0.0, 0.5, 1.0 → 3 frames
+        assert len(frames) == 3
+
+    def test_timestamps_increasing(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            frames = list(iter_frames_stepped(cap, 0.0, 2.0, 0.5))
+        timestamps = [t for t, _ in frames]
+        assert timestamps == sorted(timestamps)
+
+    def test_invalid_step_raises(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            with pytest.raises(ValueError, match="step_s"):
+                list(iter_frames_stepped(cap, 0.0, 1.0, 0.0))
+
+
+# ---------------------------------------------------------------------------
+# text_safe_crop integration (sanity: cropped height consistent)
+# ---------------------------------------------------------------------------
+
+class TestCropSanity:
+    def test_crop_reduces_height(self, synthetic_video: Path) -> None:
+        with open_video(synthetic_video) as cap:
+            frame = grab_frame_at(cap, 0.5)
+        assert frame is not None
+        cropped = text_safe_crop(frame, 0.15, 0.30)
+        assert cropped.shape[0] < frame.shape[0]
+        assert cropped.shape[1] == frame.shape[1]  # width unchanged