Add a Mac as the third system, beside Wayland and X11

Dikte already chose its clipboard programs once instead of in every
function; macOS joins that table rather than adding a branch to each one.
A Mac copies through pbcopy and presses Cmd+V straight into CoreGraphics,
records through AVFoundation, and asks Carbon for its global shortcuts.

The three tables are paste.Desktop, audio.Sound, and the pair of
predicates in hotkey.py. Each reads sys.platform inside the chooser, so a
test can stand somewhere else: 697 of the 737 tests now run on any
machine, the Wayland and X11 halves included, and the suite passes whole
whichever system it is run on.

Two things a Mac does not have needed saying rather than pretending:
there is no shortcut registry to install into, so Settings offers no
Install button and the listener is the mechanism instead of a fallback;
and nothing is offered as the sound the speakers are playing, so a
meeting needs BlackHole or Loopback and says so. The KDE-only labels
around them were already wrong on GNOME, and now name whichever desktop
is there.

Co-authored-by: firat <[email protected]>

tests/test_ui.py

@@ -6,13 +6,16 @@ save, so a setting added to one half and not the other is silently reset the
 next time anybody presses Save. That is the failure this catches.
 """
 
+import sys
 import unittest
+from typing import ClassVar
 from unittest import mock
 
 from PyQt6.QtWidgets import QApplication, QMessageBox
 
 import config as cfg
 import overlay as overlay_module
+import paste
 import settings_ui
 from tests.support import DikteTest, only_these_tools
 
@@ -80,10 +83,16 @@ CHANGED = {
 
 
 class Settings(DikteTest):
+    # What a Mac shows instead, where the combination on offer is a different
+    # one. Everything else about the window is the same on both.
+    changed = CHANGED
+    platform = "linux"
+
     def setUp(self):
         super().setUp()
         # No pactl, no model lists over the network, and no modal dialogue
         # waiting for somebody to press OK.
+        self.enterContext(mock.patch.object(sys, "platform", self.platform))
         self.enterContext(only_these_tools())
         self.enterContext(mock.patch.object(QMessageBox, "information"))
         self.enterContext(mock.patch.object(settings_ui.SettingsWindow,
@@ -116,11 +125,11 @@ class Settings(DikteTest):
         self.assertEqual(conf.data, before)
 
     def test_a_setting_of_your_own_survives_the_round_trip(self):
-        self.write_config(CHANGED)
+        self.write_config(self.changed)
         conf = cfg.Config()
         self.window(conf)._save()
         stored = self.read_config_file()
-        for key, value in CHANGED.items():
+        for key, value in self.changed.items():
             with self.subTest(key=key):
                 self.assertEqual(stored[key], value)
 
@@ -175,6 +184,34 @@ class Settings(DikteTest):
         self.assertEqual(window.windowTitle(), "Dikte Ayarları")
 
 
+class MacSettings(Settings):
+    """The same window and the same round trip, standing on a Mac.
+
+    Nothing here is about macOS: it is the rest of the window, checked on the
+    platform where three of its widgets are gone and one offers other keys.
+    """
+
+    platform = "darwin"
+    changed: ClassVar[dict] = {**CHANGED, "paste_shortcut": "cmd+shift+v"}
+
+    def test_there_is_no_install_button_where_nothing_is_installed(self):
+        window = self.window(cfg.Config())
+        labels = [button.text() for button in
+                  window.findChildren(settings_ui.QPushButton)]
+        self.assertFalse([text for text in labels if "shortcut" in text.lower()])
+
+    def test_the_listener_is_not_offered_as_a_choice(self):
+        """It is the whole mechanism there; turning it off would leave nothing."""
+        window = self.window(cfg.Config())
+        self.assertFalse(window.evdev_enabled.isVisible())
+
+    def test_the_paste_keys_on_offer_are_the_ones_a_mac_uses(self):
+        window = self.window(cfg.Config())
+        offered = [window.paste_shortcut.itemText(index)
+                   for index in range(window.paste_shortcut.count())]
+        self.assertEqual(offered, paste.MACOS.shortcuts)
+
+
 class Overlay(DikteTest):
     def overlay(self, **kwargs):
         widget = overlay_module.Overlay(**kwargs)