asynlocal: make open_async compatible with fsspec (#25)

* asynlocal: make open_async compatible with fsspec

Closes #24.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/morefs/asyn_local.py

@@ -1,7 +1,6 @@
 import shutil
 import sys
 from asyncio import get_running_loop, iscoroutinefunction
-from contextlib import asynccontextmanager
 from functools import partial, wraps
 from typing import Awaitable, Callable, TypeVar
 
@@ -83,18 +82,16 @@ async def _get_file(self, src, dst, **kwargs):  # pylint: disable=arguments-rena
             src = self._strip_protocol(src)
             return await self._get_file_async(src, dst)
 
-        async with self.open_async(src, "rb") as fsrc:
+        fsrc = await self.open_async(src, "rb")
+        async with fsrc:
             while True:
                 buf = await fsrc.read(length=shutil.COPY_BUFSIZE)
                 if not buf:
                     break
                 await dst.write(buf)
 
-    @asynccontextmanager
     async def open_async(self, path, mode="rb", **kwargs):
         path = self._strip_protocol(path)
         if self.auto_mkdir and "w" in mode:
             await self._makedirs(self._parent(path), exist_ok=True)
-
-        async with aiofile.async_open(path, mode, **kwargs) as f:
-            yield f
+        return await aiofile.async_open(path, mode, **kwargs)

src/morefs/overlay.py

@@ -6,7 +6,7 @@
 import fsspec
 
 
-class OverlayFileSystem(fsspec.AbstractFileSystem):
+class OverlayFileSystem(fsspec.AbstractFileSystem):  # pylint: disable=abstract-method
     cachable = False
 
     def __init__(self, *fses: fsspec.AbstractFileSystem, **kwargs):

tests/test_asyn_local.py

@@ -78,14 +78,17 @@ def test_sync_methods(tmp_path, localfs, fs):
 
 @pytest.mark.asyncio
 async def test_open_async(tmp_path, fs):
-    async with fs.open_async(tmp_path / "file", mode="wb") as f:
+    f = await fs.open_async(tmp_path / "file", mode="wb")
+    async with f:
         pass
     assert await fs._exists(tmp_path / "file")
 
-    async with fs.open_async(tmp_path / "file", mode="wb") as f:
+    f = await fs.open_async(tmp_path / "file", mode="wb")
+    async with f:
         assert await f.write(b"contents")
 
-    async with fs.open_async(tmp_path / "file") as f:
+    f = await fs.open_async(tmp_path / "file")
+    async with f:
         assert await f.read() == b"contents"
 
 
@@ -96,7 +99,8 @@ async def test_get_file(tmp_path, fs):
 
     assert await fs._isfile(tmp_path / "bar")
 
-    async with fs.open_async(tmp_path / "file1", mode="wb") as f:
+    f = await fs.open_async(tmp_path / "file1", mode="wb")
+    async with f:
         await fs._get_file(tmp_path / "foo", f)
     assert await fs._cat_file(tmp_path / "file1") == b"foo"
 
@@ -112,7 +116,8 @@ async def test_get_file(tmp_path, fs):
 @pytest.mark.asyncio
 async def test_auto_mkdir_on_open_async(tmp_path):
     fs = AsyncLocalFileSystem(auto_mkdir=True)
-    async with fs.open_async(tmp_path / "dir" / "file", mode="wb") as f:
+    f = await fs.open_async(tmp_path / "dir" / "file", mode="wb")
+    async with f:
         await f.write(b"contents")
 
     assert await fs._isdir(tmp_path / "dir")