[tests] Expand VFR test coverage and rework CLI tests

Use Click's CliRunner rather than subprocesses for CLI tests.

Add CSV, EDL, and expand OTIO tests for VFR and compare that the OpenCV and PyAV backends return equal results for both CFR and VFR video.

Author: Breakthrough

scenedetect/_cli/commands.py

@@ -487,6 +487,9 @@ def save_xml(
         logger.error(f"Unknown format: {format}")
 
 
+# TODO: We have to export framerate as a float for OTIO's current format. When OTIO supports
+# fractional timecodes, we should export the framerate as a rational number instead.
+# https://github.com/AcademySoftwareFoundation/OpenTimelineIO/issues/190
 def save_otio(
     context: CliContext,
     scenes: SceneList,

tests/helpers.py

@@ -0,0 +1,38 @@
+#
+#            PySceneDetect: Python-Based Video Scene Detector
+#   -------------------------------------------------------------------
+#     [  Site:    https://scenedetect.com                           ]
+#     [  Docs:    https://scenedetect.com/docs/                     ]
+#     [  Github:  https://github.com/Breakthrough/PySceneDetect/    ]
+#
+# Copyright (C) 2014-2025 Brandon Castellano <http://www.bcastell.com>.
+# PySceneDetect is licensed under the BSD 3-Clause License; see the
+# included LICENSE file, or visit one of the above pages for details.
+#
+"""Shared test helpers."""
+
+import typing as ty
+
+from click.testing import CliRunner
+
+from scenedetect._cli import scenedetect as _scenedetect_cli
+from scenedetect._cli.context import CliContext
+from scenedetect._cli.controller import run_scenedetect
+
+
+def invoke_cli(args: ty.List[str], catch_exceptions: bool = False) -> ty.Tuple[int, str]:
+    """Invoke the scenedetect CLI in-process using Click's CliRunner.
+
+    Replicates the two-step execution of ``__main__.py``:
+
+    1. ``scenedetect.main(obj=context)`` — parse args and register callbacks on ``CliContext``
+    2. ``run_scenedetect(context)`` — execute detection and output commands
+
+    Returns ``(exit_code, output_text)``.
+    """
+    context = CliContext()
+    runner = CliRunner()
+    result = runner.invoke(_scenedetect_cli, args, obj=context, catch_exceptions=catch_exceptions)
+    if result.exit_code == 0:
+        run_scenedetect(context)
+    return result.exit_code, result.output

tests/test_cli.py

@@ -38,6 +38,7 @@
 
 import scenedetect
 from scenedetect.output import is_ffmpeg_available, is_mkvmerge_available
+from tests.helpers import invoke_cli
 
 SCENEDETECT_CMD = sys.executable + " -m scenedetect"
 
@@ -303,14 +304,22 @@ def test_cli_detector_with_stats(tmp_path, detector_command: str):
 
 def test_cli_list_scenes(tmp_path: Path):
     """Test `list-scenes` command."""
-    # Regular invocation
-    assert (
-        invoke_scenedetect(
-            "-i {VIDEO} time {TIME} {DETECTOR} list-scenes",
-            output_dir=tmp_path,
-        )
-        == 0
+    exit_code, _ = invoke_cli(
+        [
+            "-i",
+            DEFAULT_VIDEO_PATH,
+            "-o",
+            str(tmp_path),
+            "time",
+            "-s",
+            "2s",
+            "-d",
+            "4s",
+            "detect-content",
+            "list-scenes",
+        ]
     )
+    assert exit_code == 0
     output_path = tmp_path.joinpath(f"{DEFAULT_VIDEO_NAME}-Scenes.csv")
     assert os.path.exists(output_path)
     EXPECTED_CSV_OUTPUT = """Timecode List:,00:00:03.754
@@ -742,13 +751,22 @@ def test_cli_load_scenes_round_trip():
 
 def test_cli_save_edl(tmp_path: Path):
     """Test `save-edl` command."""
-    assert (
-        invoke_scenedetect(
-            "-i {VIDEO} time {TIME} {DETECTOR} save-edl",
-            output_dir=tmp_path,
-        )
-        == 0
+    exit_code, _ = invoke_cli(
+        [
+            "-i",
+            DEFAULT_VIDEO_PATH,
+            "-o",
+            str(tmp_path),
+            "time",
+            "-s",
+            "2s",
+            "-d",
+            "4s",
+            "detect-content",
+            "save-edl",
+        ]
     )
+    assert exit_code == 0
     output_path = tmp_path.joinpath(f"{DEFAULT_VIDEO_NAME}.edl")
     assert os.path.exists(output_path)
     EXPECTED_EDL_OUTPUT = f"""* CREATED WITH PYSCENEDETECT {scenedetect.__version__}
@@ -763,13 +781,28 @@ def test_cli_save_edl(tmp_path: Path):
 
 def test_cli_save_edl_with_params(tmp_path: Path):
     """Test `save-edl` command but override the other options."""
-    assert (
-        invoke_scenedetect(
-            "-i {VIDEO} time {TIME} {DETECTOR} save-edl -t title -r BX -f file_no_ext",
-            output_dir=tmp_path,
-        )
-        == 0
+    exit_code, _ = invoke_cli(
+        [
+            "-i",
+            DEFAULT_VIDEO_PATH,
+            "-o",
+            str(tmp_path),
+            "time",
+            "-s",
+            "2s",
+            "-d",
+            "4s",
+            "detect-content",
+            "save-edl",
+            "-t",
+            "title",
+            "-r",
+            "BX",
+            "-f",
+            "file_no_ext",
+        ]
     )
+    assert exit_code == 0
     output_path = tmp_path.joinpath("file_no_ext")
     assert os.path.exists(output_path)
     EXPECTED_EDL_OUTPUT = f"""* CREATED WITH PYSCENEDETECT {scenedetect.__version__}
@@ -784,13 +817,22 @@ def test_cli_save_edl_with_params(tmp_path: Path):
 
 def test_cli_save_otio(tmp_path: Path):
     """Test `save-otio` command."""
-    assert (
-        invoke_scenedetect(
-            "-i {VIDEO} time {TIME} {DETECTOR} save-otio",
-            output_dir=tmp_path,
-        )
-        == 0
+    exit_code, _ = invoke_cli(
+        [
+            "-i",
+            DEFAULT_VIDEO_PATH,
+            "-o",
+            str(tmp_path),
+            "time",
+            "-s",
+            "2s",
+            "-d",
+            "4s",
+            "detect-content",
+            "save-otio",
+        ]
     )
+    assert exit_code == 0
     output_path = tmp_path.joinpath(f"{DEFAULT_VIDEO_NAME}.otio")
     assert os.path.exists(output_path)
     EXPECTED_OTIO_OUTPUT = """{
@@ -992,13 +1034,23 @@ def test_cli_save_otio(tmp_path: Path):
 
 def test_cli_save_otio_no_audio(tmp_path: Path):
     """Test `save-otio` command without audio."""
-    assert (
-        invoke_scenedetect(
-            "-i {VIDEO} time {TIME} {DETECTOR} save-otio --no-audio",
-            output_dir=tmp_path,
-        )
-        == 0
+    exit_code, _ = invoke_cli(
+        [
+            "-i",
+            DEFAULT_VIDEO_PATH,
+            "-o",
+            str(tmp_path),
+            "time",
+            "-s",
+            "2s",
+            "-d",
+            "4s",
+            "detect-content",
+            "save-otio",
+            "--no-audio",
+        ]
     )
+    assert exit_code == 0
     output_path = tmp_path.joinpath(f"{DEFAULT_VIDEO_NAME}.otio")
     assert os.path.exists(output_path)
     EXPECTED_OTIO_OUTPUT = """{