Add GUI tests for config and camera fallback

Expand main window GUI coverage with a regression test that ensures runtime camera fallback updates only the active inference camera, not the user’s preferred inference camera. Add a new test module for user-config persistence, covering config path validation, dialog path suggestion logic, successful save side effects (last path, snapshot, sync), and failure behavior that avoids persistence and reports errors. Also add file header comments in related test files.

Author: C-Achard

tests/gui/main_window/test_preview.py

@@ -1,9 +1,14 @@
+# tests/gui/main_window/test_preview.py
 from __future__ import annotations
 
+from types import SimpleNamespace
+
 import numpy as np
 import pytest
 from PySide6.QtGui import QPixmap
 
+from dlclivegui.services.multi_camera_controller import get_camera_id
+
 
 @pytest.mark.gui
 class TestPreviewLifecycle:
@@ -85,3 +90,35 @@ def test_on_multi_camera_started_updates_primary_buttons(self, window):
 
         assert not w.preview_button.isEnabled()
         assert w.stop_preview_button.isEnabled()
+
+    def test_processing_runtime_fallback_does_not_overwrite_preferred_inference_camera(self, window):
+        w = window
+
+        active_cams = w._config.multi_camera.get_active_cameras()
+        if len(active_cams) < 2:
+            pytest.skip("This regression test requires at least two active cameras.")
+
+        fallback_cam = active_cams[0]
+        preferred_cam = active_cams[1]
+
+        fallback_id = get_camera_id(fallback_cam)
+        preferred_id = get_camera_id(preferred_cam)
+
+        w._inference_camera_id = preferred_id
+        w._active_inference_camera_id = preferred_id
+        w._running_cams_ids = set()
+        w._dlc_active = False
+
+        frame = np.zeros((4, 4, 3), dtype=np.uint8)
+        frame_data = SimpleNamespace(
+            frames={fallback_id: frame},
+            display_ids={fallback_id: "Fallback camera"},
+            source_camera_id=fallback_id,
+            timestamps={fallback_id: 123.0},
+        )
+
+        w._on_multi_frame_processing_ready(frame_data)
+
+        assert w._inference_camera_id == preferred_id
+        assert w._active_inference_camera_id == fallback_id
+        assert w.dlc_camera_combo.currentData() == fallback_id

tests/gui/main_window/test_recording.py

@@ -1,3 +1,4 @@
+# tests/gui/main_window/test_recording.py
 from __future__ import annotations
 
 import numpy as np

tests/gui/main_window/test_ui.py

@@ -1,3 +1,4 @@
+# tests/gui/main_window/test_ui.py
 from __future__ import annotations
 
 import pytest

tests/gui/main_window/test_user_config.py

@@ -0,0 +1,142 @@
+# tests/gui/main_window/test_user_config.py
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+
+@pytest.mark.gui
+class TestUserConfigPersistence:
+    def test_valid_config_file_path_accepts_existing_file(self, window, tmp_path: Path):
+        w = window
+
+        config_path = tmp_path / "dlclive_config.json"
+        config_path.write_text("{}", encoding="utf-8")
+
+        assert w._valid_config_file_path(str(config_path)) == config_path.resolve()
+
+    def test_valid_config_file_path_rejects_missing_file(self, window, tmp_path: Path):
+        w = window
+
+        missing = tmp_path / "missing_config.json"
+
+        assert w._valid_config_file_path(str(missing)) is None
+        assert w._valid_config_file_path(None) is None
+        assert w._valid_config_file_path("") is None
+
+    def test_suggest_config_dialog_path_prefers_current_config_path(self, window, tmp_path: Path):
+        w = window
+
+        config_path = tmp_path / "current_config.json"
+        config_path.write_text("{}", encoding="utf-8")
+
+        w._config_path = config_path
+
+        assert w._suggest_config_dialog_path() == str(config_path)
+
+    def test_suggest_config_dialog_path_uses_last_config_path_when_current_path_missing(
+        self,
+        monkeypatch,
+        window,
+        tmp_path: Path,
+    ):
+        w = window
+
+        config_path = tmp_path / "last_config.json"
+        config_path.write_text("{}", encoding="utf-8")
+
+        w._config_path = None
+        monkeypatch.setattr(w._settings_store, "get_last_config_path", lambda: str(config_path))
+
+        assert w._suggest_config_dialog_path() == str(config_path.resolve())
+
+    def test_suggest_config_dialog_path_uses_parent_of_missing_last_config(
+        self,
+        monkeypatch,
+        window,
+        tmp_path: Path,
+    ):
+        w = window
+
+        missing_config_path = tmp_path / "missing_config.json"
+
+        w._config_path = None
+        monkeypatch.setattr(w._settings_store, "get_last_config_path", lambda: str(missing_config_path))
+
+        assert w._suggest_config_dialog_path() == str(missing_config_path)
+
+    def test_save_config_to_path_persists_last_path_snapshot_and_syncs(
+        self,
+        monkeypatch,
+        window,
+        tmp_path: Path,
+    ):
+        w = window
+
+        calls: list[tuple[str, object]] = []
+
+        class FakeConfig:
+            def save(self, path: Path | str) -> None:
+                Path(path).write_text("{}", encoding="utf-8")
+
+        class FakeSettings:
+            def sync(self) -> None:
+                calls.append(("sync", True))
+
+        config_path = tmp_path / "saved_config.json"
+        fake_config = FakeConfig()
+
+        monkeypatch.setattr(w, "_current_config", lambda allow_empty_model_path=False: fake_config)
+        monkeypatch.setattr(
+            w._settings_store,
+            "set_last_config_path",
+            lambda path: calls.append(("last_path", path)),
+        )
+        monkeypatch.setattr(
+            w._settings_store,
+            "save_full_config_snapshot",
+            lambda cfg: calls.append(("snapshot", cfg)),
+        )
+        monkeypatch.setattr(w, "settings", FakeSettings())
+
+        assert w._save_config_to_path(config_path) is True
+        assert config_path.exists()
+        assert ("last_path", str(config_path.resolve())) in calls
+        assert ("snapshot", fake_config) in calls
+        assert ("sync", True) in calls
+
+    def test_save_config_to_path_returns_false_without_persisting_after_failure(
+        self,
+        monkeypatch,
+        window,
+        tmp_path: Path,
+    ):
+        w = window
+
+        calls: list[tuple[str, object]] = []
+        errors: list[str] = []
+
+        class FakeConfig:
+            def save(self, path: Path | str) -> None:
+                raise OSError("cannot save")
+
+        config_path = tmp_path / "failed_config.json"
+
+        monkeypatch.setattr(w, "_current_config", lambda allow_empty_model_path=False: FakeConfig())
+        monkeypatch.setattr(
+            w._settings_store,
+            "set_last_config_path",
+            lambda path: calls.append(("last_path", path)),
+        )
+        monkeypatch.setattr(
+            w._settings_store,
+            "save_full_config_snapshot",
+            lambda cfg: calls.append(("snapshot", cfg)),
+        )
+        monkeypatch.setattr(w, "_show_error", errors.append)
+
+        assert w._save_config_to_path(config_path) is False
+        assert not config_path.exists()
+        assert calls == []
+        assert errors