feat: add ColorAwareApp mixin (resolves #465)

tests/test_colorscheme.py

@@ -0,0 +1,59 @@
+import pytest
+import subprocess
+
+from dzgui.const.constants import GIO_SETTINGS_KEY
+from dzgui.views.mixins.colorscheme import ColorAwareApp
+
+import gi
+
+gi.require_version("Gtk", "3.0")
+from gi.repository import Gtk, Gio, GLib  # noqa
+
+
+class TestWidget(ColorAwareApp, Gtk.Button):
+    def __init__(self) -> None:
+        super().__init__()
+
+        self.state: bool
+
+    def check_theme(self) -> None:
+        self.state = self.get_settings().get_property(GIO_SETTINGS_KEY)
+        Gtk.main_quit()
+
+
+@pytest.fixture
+def widget() -> TestWidget:
+    return TestWidget()
+
+
+@pytest.mark.integration
+@pytest.mark.parametrize("key, expect", [("default", False), ("prefer-dark", True)])
+def test_light_mode(widget, key: str, expect: bool) -> None:
+    local_pref = subprocess.run(
+        ["gsettings", "get", "org.gnome.desktop.interface", "color-scheme"],
+        capture_output=True,
+        text=True,
+    ).stdout
+    subprocess.run(
+        [
+            "gsettings",
+            "set",
+            "org.gnome.desktop.interface",
+            "color-scheme",
+            key,
+        ],
+    )
+
+    # NOTE: allow changes to propagate
+    GLib.idle_add(widget.check_theme)
+    Gtk.main()
+    subprocess.run(
+        [
+            "gsettings",
+            "set",
+            "org.gnome.desktop.interface",
+            "color-scheme",
+            local_pref,
+        ]
+    )
+    assert widget.state is expect