Fix hot reloading for Python 3.9

pyproject.toml

@@ -52,7 +52,9 @@ dependencies = [
 optional-dependencies.docs = [
 ]
 optional-dependencies.test = [
+  "asgi-lifespan",
   "httpx",
+  "httpx-ws",
   "pytest>=6",
 ]
 urls.Changelog = "https://github.com/sphinx-doc/sphinx-autobuild/blob/main/NEWS.rst"

sphinx_autobuild/server.py

@@ -28,11 +28,11 @@ def __init__(
         self.paths = [Path(path).resolve(strict=True) for path in paths]
         self.ignore = ignore_filter
         self.change_callback = change_callback
-        self.flag = asyncio.Event()
-        self.should_exit = asyncio.Event()
 
     @asynccontextmanager
     async def lifespan(self, _app) -> AbstractAsyncContextManager[None]:
+        self.flag = asyncio.Event()
+        self.should_exit = asyncio.Event()
         task = asyncio.create_task(self.main())
         yield
         self.should_exit.set()

tests/test_application.py

@@ -3,7 +3,12 @@
 import shutil
 from pathlib import Path
 
-from starlette.testclient import TestClient
+import anyio
+import httpx
+import pytest
+from asgi_lifespan import LifespanManager
+from httpx_ws import aconnect_ws
+from httpx_ws.transport import ASGIWebSocketTransport
 
 from sphinx_autobuild.__main__ import _create_app
 from sphinx_autobuild.build import Builder
@@ -12,21 +17,39 @@
 ROOT = Path(__file__).parent.parent
 
 
-def test_application(tmp_path):
+@pytest.fixture
+def anyio_backend():
+    return "asyncio"
+
+
+async def test_application(tmp_path, anyio_backend):  # noqa: ARG001
     src_dir = tmp_path / "docs"
     out_dir = tmp_path / "build"
     shutil.copytree(ROOT / "docs", tmp_path / "docs")
     out_dir.mkdir(parents=True, exist_ok=True)
+    index_file = anyio.Path(src_dir / "index.rst")
+    await index_file.write_text("hello")
 
     url_host = "127.0.0.1:7777"
     ignore_handler = IgnoreFilter([out_dir], [])
     builder = Builder(
         [str(src_dir), str(out_dir)], url_host=url_host, pre_build_commands=[]
     )
     app = _create_app([src_dir], ignore_handler, builder, out_dir, url_host)
-    client = TestClient(app)
 
-    builder(changed_paths=())
+    async with (
+        LifespanManager(app) as manager,
+        httpx.AsyncClient(
+            transport=ASGIWebSocketTransport(manager.app), base_url="http://testserver"
+        ) as client,
+    ):
+        builder(changed_paths=())
+
+        response = await client.get("/")
+        assert response.status_code == 200
+
+        async with aconnect_ws("/websocket-reload", client) as websocket:
+            await index_file.write_text("world")
 
-    response = client.get("/")
-    assert response.status_code == 200
+            data = await websocket.receive_text()
+            assert data == "refresh"