Added OS-specific tests for

src/trio/_path.py

@@ -246,9 +246,7 @@ def __repr__(self) -> str:
 
 @final
 class PosixPath(Path, pathlib.PurePosixPath):
-    """An async :class:`pathlib.PosixPath` that executes blocking methods in :meth:`trio.to_thread.run_sync`.
-
-    """
+    """An async :class:`pathlib.PosixPath` that executes blocking methods in :meth:`trio.to_thread.run_sync`."""
 
     __slots__ = ()
 
@@ -257,9 +255,7 @@ class PosixPath(Path, pathlib.PurePosixPath):
 
 @final
 class WindowsPath(Path, pathlib.PureWindowsPath):
-    """An async :class:`pathlib.WindowsPath` that executes blocking methods in :meth:`trio.to_thread.run_sync`.
-
-    """
+    """An async :class:`pathlib.WindowsPath` that executes blocking methods in :meth:`trio.to_thread.run_sync`."""
 
     __slots__ = ()
 

src/trio/_tests/test_path.py

@@ -27,6 +27,16 @@ def method_pair(
     return getattr(sync_path, method_name), getattr(async_path, method_name)
 
 
+@pytest.mark.skipif(os.name == "nt", reason="OS is not posix")
+async def test_instantiate_posix() -> None:
+    assert isinstance(trio.Path(), trio.PosixPath)
+
+
+@pytest.mark.skipif(os.name != "nt", reason="OS is not Windows")
+async def test_instantiate_windows() -> None:
+    assert isinstance(trio.Path(), trio.WindowsPath)
+
+
 async def test_open_is_async_context_manager(path: trio.Path) -> None:
     async with await path.open("w") as f:
         assert isinstance(f, AsyncIOWrapper)