Different Eventloops on windows can now be explored

aiodns/__init__.py

@@ -27,7 +27,8 @@
 _T = TypeVar('_T')
 
 WINDOWS_SELECTOR_ERR_MSG = (
-    'aiodns needs a SelectorEventLoop on Windows. See more: '
+    'aiodns cannot use ProactorEventLoop on Windows'
+    ' if pycares has no threadsafety. See more: '
     'https://github.com/aio-libs/aiodns#note-for-windows-users'
 )
 
@@ -106,16 +107,13 @@ def _make_channel(self, **kwargs: Any) -> tuple[bool, pycares.Channel]:
                         'Falling back to socket state callback: %s',
                         e,
                     )
-        if sys.platform == 'win32' and not isinstance(
-            self.loop, asyncio.SelectorEventLoop
-        ):
-            try:
-                import winloop
+        if sys.platform == 'win32':
+            if (
+                hasattr(asyncio, 'ProactorEventLoop')
+                and type(self.loop) is asyncio.ProactorEventLoop
+            ):
+                raise RuntimeError(WINDOWS_SELECTOR_ERR_MSG)
 
-                if not isinstance(self.loop, winloop.Loop):
-                    raise RuntimeError(WINDOWS_SELECTOR_ERR_MSG)
-            except ModuleNotFoundError as ex:
-                raise RuntimeError(WINDOWS_SELECTOR_ERR_MSG) from ex
         return False, pycares.Channel(
             sock_state_cb=self._sock_state_cb, timeout=self._timeout, **kwargs
         )

tests/test_aiodns.py

@@ -9,7 +9,6 @@
 import time
 import unittest
 import unittest.mock
-from typing import Any
 
 import pycares
 import pytest
@@ -328,27 +327,6 @@ def setUp(self) -> None:
             super().setUp()
 
 
-@unittest.skipIf(sys.platform != 'win32', 'Only run on Windows')
-def test_win32_no_selector_event_loop() -> None:
-    """Test DNSResolver with Windows without SelectorEventLoop."""
-    # Create a non-SelectorEventLoop to trigger the error
-    mock_loop = unittest.mock.MagicMock(spec=asyncio.AbstractEventLoop)
-    mock_loop.__class__ = (
-        asyncio.AbstractEventLoop  # type: ignore[assignment]
-    )
-
-    with (
-        pytest.raises(
-            RuntimeError, match='aiodns needs a SelectorEventLoop on Windows'
-        ),
-        unittest.mock.patch(
-            'aiodns.pycares.ares_threadsafety', return_value=False
-        ),
-        unittest.mock.patch('sys.platform', 'win32'),
-    ):
-        aiodns.DNSResolver(loop=mock_loop, timeout=5.0)
-
-
 @pytest.mark.parametrize(
     ('platform', 'expected_msg_parts', 'unexpected_msg_parts'),
     [
@@ -440,132 +418,26 @@ async def test_make_channel_ares_error(
         resolver._closed = True
 
 
-def test_win32_import_winloop_error() -> None:
-    """Test winloop import error on Windows.
-
-    Test handling of ModuleNotFoundError when importing
-    winloop on Windows.
-    """
-    # Create a mock event loop that is not a SelectorEventLoop
-    mock_loop = unittest.mock.MagicMock(spec=asyncio.AbstractEventLoop)
-
-    # Setup patching for this test
-    original_import = __import__
-
-    def mock_import(name: str, *args: Any, **kwargs: Any) -> Any:
-        if name == 'winloop':
-            raise ModuleNotFoundError("No module named 'winloop'")
-        return original_import(name, *args, **kwargs)
-
-    # Patch the Channel class to avoid creating real network resources
-    mock_channel = unittest.mock.MagicMock()
-
-    with (
-        unittest.mock.patch('sys.platform', 'win32'),
-        unittest.mock.patch(
-            'aiodns.pycares.ares_threadsafety', return_value=False
-        ),
-        unittest.mock.patch('builtins.__import__', side_effect=mock_import),
-        unittest.mock.patch(
-            'importlib.import_module', side_effect=mock_import
-        ),
-        # Also patch Channel creation to avoid socket resource leak
-        unittest.mock.patch(
-            'aiodns.pycares.Channel', return_value=mock_channel
-        ),
-        pytest.raises(RuntimeError, match=aiodns.WINDOWS_SELECTOR_ERR_MSG),
-    ):
-        aiodns.DNSResolver(loop=mock_loop)
-
-
-def test_win32_winloop_not_loop_instance() -> None:
-    """Test non-winloop.Loop instance on Windows.
-
-    Test handling of a loop that is not a winloop.Loop
-    instance on Windows.
-    """
-    # Create a mock event loop that is not a SelectorEventLoop
-    mock_loop = unittest.mock.MagicMock(spec=asyncio.AbstractEventLoop)
-
-    original_import = __import__
-
-    # Create a mock winloop module with a Loop class that's an actual type
-    class MockLoop:
-        pass
-
-    mock_winloop_module = unittest.mock.MagicMock()
-    mock_winloop_module.Loop = MockLoop
-
-    def mock_import(name: str, *args: Any, **kwargs: Any) -> Any:
-        if name == 'winloop':
-            return mock_winloop_module
-        return original_import(name, *args, **kwargs)
-
-    # Patch the Channel class to avoid creating real network resources
-    mock_channel = unittest.mock.MagicMock()
-
-    with (
-        unittest.mock.patch('sys.platform', 'win32'),
-        unittest.mock.patch(
-            'aiodns.pycares.ares_threadsafety', return_value=False
-        ),
-        unittest.mock.patch('builtins.__import__', side_effect=mock_import),
-        unittest.mock.patch(
-            'importlib.import_module', side_effect=mock_import
-        ),
-        # Also patch Channel creation to avoid socket resource leak
-        unittest.mock.patch(
-            'aiodns.pycares.Channel', return_value=mock_channel
-        ),
-        pytest.raises(RuntimeError, match=aiodns.WINDOWS_SELECTOR_ERR_MSG),
-    ):
-        aiodns.DNSResolver(loop=mock_loop)
-
-
-def test_win32_winloop_loop_instance() -> None:
-    """Test winloop.Loop instance on Windows.
-
-    Test handling of a loop that IS a winloop.Loop instance on Windows.
-    """
-
-    # Create a mock winloop module with a Loop class
-    class MockLoop:
-        pass
-
-    # Create a mock event loop that IS a winloop.Loop instance
-    mock_loop = unittest.mock.MagicMock(spec=asyncio.AbstractEventLoop)
-    # Make isinstance check pass
-    mock_loop.__class__ = MockLoop  # type: ignore[assignment]
-
-    mock_winloop_module = unittest.mock.MagicMock()
-    mock_winloop_module.Loop = MockLoop
-
-    original_import = __import__
-
-    def mock_import(name: str, *args: Any, **kwargs: Any) -> Any:
-        if name == 'winloop':
-            return mock_winloop_module
-        return original_import(name, *args, **kwargs)
-
-    # Mock channel creation to avoid actual DNS resolution
-    mock_channel = unittest.mock.MagicMock()
-
+@pytest.mark.skipif(
+    sys.platform != 'win32',
+    reason="ProactorEventLoop can't be simulated",
+)
+@pytest.mark.asyncio
+async def test_runtime_error_if_windows_proactor_event_loop() -> None:
     with (
-        unittest.mock.patch('sys.platform', 'win32'),
         unittest.mock.patch(
             'aiodns.pycares.ares_threadsafety', return_value=False
         ),
-        unittest.mock.patch('builtins.__import__', side_effect=mock_import),
-        unittest.mock.patch(
-            'importlib.import_module', side_effect=mock_import
-        ),
-        unittest.mock.patch(
-            'aiodns.pycares.Channel', return_value=mock_channel
+        pytest.raises(
+            RuntimeError,
+            match=r'aiodns cannot use ProactorEventLoop on Windows'
+            r' if pycares has no threadsafety. See more: '
+            r'https://github.com/aio-libs/aiodns#note-for-windows-users',
         ),
     ):
-        # This should not raise an exception since loop
-        # is a winloop.Loop instance
-        aiodns.DNSResolver(loop=mock_loop)
+        # The ProactorEventLoop is chosen by default
+        async with aiodns.DNSResolver():
+            pass
 
 
 @pytest.mark.asyncio