After story 3

tests/test_story_03.py

@@ -0,0 +1,67 @@
+import shutil
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "src"))
+
+from frame_sampler import FrameSampler, calculate_timestamps
+from scratch_manager import ScratchManager
+
+
+class Story03SamplingTests(unittest.TestCase):
+    def test_calculate_timestamps_uses_uniform_temporal_spacing(self):
+        stamps = calculate_timestamps(duration=90.0, interval=30.0)
+        self.assertEqual(stamps, [0.0, 30.0, 60.0])
+
+    def test_frame_sampler_builds_ffmpeg_command_with_scale_and_jpeg_output(self):
+        sampler = FrameSampler(interval_seconds=30, quality=2, output_format="jpeg")
+        command = sampler._build_ffmpeg_command(
+            video_path="/tmp/video.mp4",
+            output_path="/tmp/out.jpg",
+            timestamp=12.5,
+            resolution=(3840, 2160),
+        )
+
+        self.assertIn("ffmpeg", command[0])
+        self.assertIn("-ss", command)
+        self.assertIn("-vframes", command)
+        self.assertIn("scale=1920:1080", " ".join(command))
+        self.assertTrue(command[-1].endswith("out.jpg"))
+
+    def test_frame_sampler_uses_subprocess_and_returns_output_path(self):
+        sampler = FrameSampler(interval_seconds=30, quality=2, output_format="jpeg")
+        with tempfile.TemporaryDirectory() as tmpdir:
+            video_path = Path(tmpdir) / "sample.mp4"
+            output_path = Path(tmpdir) / "frame.jpg"
+            video_path.write_bytes(b"fake")
+
+            def _mock_run(*args, **kwargs):
+                output_path.write_bytes(b"frame")
+                return type("Completed", (), {"returncode": 0, "stdout": b"", "stderr": b""})()
+
+            with patch("subprocess.run", side_effect=_mock_run):
+                result = sampler.extract_frame(
+                    video_path=str(video_path),
+                    output_path=str(output_path),
+                    timestamp=15.0,
+                    resolution=(1280, 720),
+                )
+
+            self.assertTrue(result)
+            self.assertEqual(output_path.name, Path(result).name)
+
+    def test_scratch_manager_cleans_up_frames_after_processing(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            manager = ScratchManager(base_path=tmpdir, video_id="video-1", auto_cleanup=True)
+            frame_dir = manager.ensure_frame_dir()
+            (frame_dir / "video-1_1000.jpg").write_bytes(b"frame")
+
+            manager.cleanup()
+            self.assertFalse(frame_dir.exists())
+
+
+if __name__ == "__main__":
+    unittest.main()