feat(theme): added theme handler to bec widget base class; added tests

tests/unit_tests/conftest.py

@@ -14,6 +14,8 @@ def qapplication(qtbot):  # pylint: disable=unused-argument
     qapp = QApplication.instance()
     # qapp.quit()
     qapp.processEvents()
+    if hasattr(qapp, "os_listener") and qapp.os_listener:
+        qapp.removeEventFilter(qapp.os_listener)
     try:
         qtbot.waitUntil(lambda: qapp.topLevelWidgets() == [])
     except QtBotTimeoutError as exc:

tests/unit_tests/test_dark_mode_button.py

@@ -2,6 +2,7 @@ from unittest import mock
 
 import pytest
 from qtpy.QtCore import Qt
+from qtpy.QtWidgets import QApplication
 
 from bec_widgets.utils.colors import set_theme
 from bec_widgets.widgets.dark_mode_button.dark_mode_button import DarkModeButton
@@ -70,3 +71,16 @@ def test_dark_mode_button_changes_theme(dark_mode_button):
 
         dark_mode_button.toggle_dark_mode()
         mocked_set_theme.assert_called_with("light")
+
+
+def test_dark_mode_button_changes_on_os_theme_change(qtbot, dark_mode_button):
+    """
+    Test that the dark mode button changes the theme correctly when the OS theme changes.
+    """
+    qapp = QApplication.instance()
+    assert dark_mode_button.dark_mode_enabled is False
+    assert dark_mode_button.mode_button.toolTip() == "Set Dark Mode"
+    qapp.theme_signal.theme_updated.emit("dark")
+    qtbot.wait(100)
+    assert dark_mode_button.dark_mode_enabled is True
+    assert dark_mode_button.mode_button.toolTip() == "Set Light Mode"

tests/unit_tests/test_vscode_widget.py

@@ -61,7 +61,7 @@ def test_vscode_cleanup(qtbot, patched_vscode_process):
     vscode_patched, mock_killpg = patched_vscode_process
     vscode_patched.process.pid = 123
     vscode_patched.process.poll.return_value = None
-    vscode_patched.cleanup()
+    vscode_patched.cleanup_vscode()
     mock_killpg.assert_called_once_with(123, 15)
     vscode_patched.process.wait.assert_called_once()
 
@@ -70,6 +70,6 @@ def test_close_event_on_terminated_code(qtbot, patched_vscode_process):
     vscode_patched, mock_killpg = patched_vscode_process
     vscode_patched.process.pid = 123
     vscode_patched.process.poll.return_value = 0
-    vscode_patched.cleanup()
+    vscode_patched.cleanup_vscode()
     mock_killpg.assert_not_called()
     vscode_patched.process.wait.assert_not_called()

tests/unit_tests/test_waveform_widget.py

@@ -2,8 +2,11 @@ from unittest.mock import MagicMock, patch
 
 import pyqtgraph as pg
 import pytest
+from qtpy.QtGui import QColor
+from qtpy.QtWidgets import QApplication
 
 from bec_widgets.qt_utils.settings_dialog import SettingsDialog
+from bec_widgets.utils.colors import apply_theme, get_theme_palette, set_theme
 from bec_widgets.widgets.figure.plots.axis_settings import AxisSettings
 from bec_widgets.widgets.waveform.waveform_popups.curve_dialog.curve_dialog import CurveSettings
 from bec_widgets.widgets.waveform.waveform_widget import BECWaveformWidget
@@ -460,3 +463,42 @@ def test_axis_dialog_set_properties(qtbot, waveform_widget):
     assert waveform_widget._config_dict["axis"]["y_scale"] == "linear"
     assert waveform_widget._config_dict["axis"]["x_lim"] == (5, 15)
     assert waveform_widget._config_dict["axis"]["y_lim"] == (5, 15)
+
+
+def test_waveform_widget_theme_update(qtbot, waveform_widget):
+    """Test theme update for waveform widget."""
+    qapp = QApplication.instance()
+
+    # Set the theme directly; equivalent to clicking the dark mode button
+    # The background color should be black and the axis color should be white
+    set_theme("dark")
+    palette = get_theme_palette()
+    waveform_color_dark = waveform_widget.waveform.plot_item.getAxis("left").pen().color()
+    bg_color = waveform_widget.fig.backgroundBrush().color()
+    assert bg_color == QColor("black")
+    assert waveform_color_dark == palette.text().color()
+
+    # Set the theme to light; equivalent to clicking the light mode button
+    # The background color should be white and the axis color should be black
+    set_theme("light")
+    palette = get_theme_palette()
+    waveform_color_light = waveform_widget.waveform.plot_item.getAxis("left").pen().color()
+    bg_color = waveform_widget.fig.backgroundBrush().color()
+    assert bg_color == QColor("white")
+    assert waveform_color_light == palette.text().color()
+
+    assert waveform_color_dark != waveform_color_light
+
+    # Set the theme to auto; equivalent starting the application with no theme set
+    set_theme("auto")
+    # Simulate that the OS theme changes to dark
+    qapp.theme_signal.theme_updated.emit("dark")
+    apply_theme("dark")
+
+    # The background color should be black and the axis color should be white
+    # As we don't have access to the listener here, we can't test the palette change. Instead,
+    # we compare the waveform color to the dark theme color
+    waveform_color = waveform_widget.waveform.plot_item.getAxis("left").pen().color()
+    bg_color = waveform_widget.fig.backgroundBrush().color()
+    assert bg_color == QColor("black")
+    assert waveform_color == waveform_color_dark