fix(macos): address fifth round of Copilot review feedback

Author: ShresthSamyak

mpv.py

@@ -1059,7 +1059,10 @@ def _wait_for_future(self, result, timeout):
             start_time = time.monotonic()
             try:
                 if _core_foundation is None or _cf_runloop_default_mode is None:
-                    _core_foundation = ctypes.cdll.LoadLibrary(ctypes.util.find_library('CoreFoundation'))
+                    core_foundation_path = ctypes.util.find_library('CoreFoundation')
+                    if not core_foundation_path:
+                        raise OSError("CoreFoundation library not found")
+                    _core_foundation = ctypes.cdll.LoadLibrary(core_foundation_path)
 
                     # CFRunLoopRunInMode(CFStringRef mode, CFTimeInterval seconds, Boolean returnAfterSourceHandled)
                     _core_foundation.CFRunLoopRunInMode.argtypes = [ctypes.c_void_p, ctypes.c_double, ctypes.c_bool]

tests/test_mpv.py

@@ -1011,6 +1011,7 @@ def test_macos_wait_for_future(self):
             mock_cf = mock.Mock()
             mock_load_library.return_value = mock_cf
             mock_in_dll.return_value = mock.Mock()
+            mock_find_library.return_value = 'CoreFoundation'
 
             # Reset globals from mpv module to force re-initialization
             orig_cf = mpv._core_foundation
@@ -1054,6 +1055,7 @@ def test_macos_wait_for_future_timeout(self):
             mock_cf = mock.Mock()
             mock_load_library.return_value = mock_cf
             mock_in_dll.return_value = mock.Mock()
+            mock_find_library.return_value = 'CoreFoundation'
 
             orig_cf = mpv._core_foundation
             orig_mode = mpv._cf_runloop_default_mode
@@ -1084,8 +1086,8 @@ def test_macos_wait_for_future_fallback(self):
             mock_current_thread.return_value = sentinel
             mock_main_thread.return_value = sentinel
 
-            # Force CoreFoundation init to fail
-            mock_load_library.side_effect = OSError("Library not found")
+            # Force CoreFoundation init to fail by having find_library return None
+            mock_find_library.return_value = None
 
             orig_cf = mpv._core_foundation
             orig_mode = mpv._cf_runloop_default_mode