feat: add FFmpeg command parser with path resolution

tests/test_ffmpeg.py

@@ -0,0 +1,59 @@
+import pytest
+
+from app.ffmpeg import parse_command, resolve_paths
+
+
+def test_parse_simple_command():
+    command = "-i input.mp4 output.mp4"
+
+    args = parse_command(command)
+
+    assert args == ["-i", "input.mp4", "output.mp4"]
+
+
+def test_parse_command_with_options():
+    command = "-i input.mp4 -c:v libx264 -crf 23 output.mp4"
+
+    args = parse_command(command)
+
+    assert args == ["-i", "input.mp4", "-c:v", "libx264", "-crf", "23", "output.mp4"]
+
+
+def test_parse_command_with_quotes():
+    command = '-i "input file.mp4" output.mp4'
+
+    args = parse_command(command)
+
+    assert args == ["-i", "input file.mp4", "output.mp4"]
+
+
+def test_resolve_paths():
+    args = ["-i", "input/video.mp4", "-c:v", "libx264", "output/result.mp4"]
+    data_path = "/data"
+
+    resolved = resolve_paths(args, data_path)
+
+    assert resolved == [
+        "-i", "/data/input/video.mp4",
+        "-c:v", "libx264",
+        "/data/output/result.mp4"
+    ]
+
+
+def test_resolve_paths_preserves_absolute():
+    args = ["-i", "/already/absolute.mp4", "output.mp4"]
+    data_path = "/data"
+
+    resolved = resolve_paths(args, data_path)
+
+    assert resolved == ["-i", "/already/absolute.mp4", "/data/output.mp4"]
+
+
+def test_resolve_paths_skips_options():
+    args = ["-c:v", "libx264", "-preset", "fast"]
+    data_path = "/data"
+
+    resolved = resolve_paths(args, data_path)
+
+    # Options and their values should not be resolved as paths
+    assert resolved == ["-c:v", "libx264", "-preset", "fast"]