test(dark_mode_button): added tests for dark mode button

tests/unit_tests/test_dark_mode_button.py

@@ -0,0 +1,70 @@
+from unittest import mock
+
+import pytest
+from qtpy.QtCore import Qt
+
+from bec_widgets.widgets.dark_mode_button.dark_mode_button import DarkModeButton
+
+# pylint: disable=unused-import
+from .client_mocks import mocked_client
+
+# pylint: disable=redefined-outer-name
+
+
+@pytest.fixture
+def dark_mode_button(qtbot, mocked_client):
+    """
+    Fixture for the dark mode button.
+    """
+    button = DarkModeButton(client=mocked_client)
+    qtbot.addWidget(button)
+    qtbot.waitExposed(button)
+    yield button
+
+
+def test_dark_mode_button_init(dark_mode_button):
+    """
+    Test that the dark mode button is initialized correctly.
+    """
+    assert dark_mode_button.dark_mode_enabled is False
+    assert dark_mode_button.mode_button.toolTip() == "Set Dark Mode"
+
+
+def test_dark_mode_button_toggle(dark_mode_button):
+    """
+    Test that the dark mode button toggles correctly.
+    """
+    dark_mode_button.set_dark_mode_enabled()
+    assert dark_mode_button.dark_mode_enabled is True
+    assert dark_mode_button.mode_button.toolTip() == "Set Light Mode"
+
+    dark_mode_button.set_dark_mode_enabled()
+    assert dark_mode_button.dark_mode_enabled == False
+    assert dark_mode_button.mode_button.toolTip() == "Set Dark Mode"
+
+
+def test_dark_mode_button_toggles_on_click(dark_mode_button, qtbot):
+    """
+    Test that the dark mode button toggles correctly when clicked.
+    """
+    qtbot.mouseClick(dark_mode_button.mode_button, Qt.MouseButton.LeftButton)
+    assert dark_mode_button.dark_mode_enabled is True
+    assert dark_mode_button.mode_button.toolTip() == "Set Light Mode"
+
+    qtbot.mouseClick(dark_mode_button.mode_button, Qt.MouseButton.LeftButton)
+    assert dark_mode_button.dark_mode_enabled is False
+    assert dark_mode_button.mode_button.toolTip() == "Set Dark Mode"
+
+
+def test_dark_mode_button_changes_theme(dark_mode_button):
+    """
+    Test that the dark mode button changes the theme correctly.
+    """
+    with mock.patch(
+        "bec_widgets.widgets.dark_mode_button.dark_mode_button.set_theme"
+    ) as mocked_set_theme:
+        dark_mode_button.set_dark_mode_enabled()
+        mocked_set_theme.assert_called_with("dark")
+
+        dark_mode_button.set_dark_mode_enabled()
+        mocked_set_theme.assert_called_with("light")