lock on windows platform using multiple workers

tests/conftest.py

@@ -10,7 +10,7 @@
 
 
 @asynccontextmanager
-async def _server(interface, port, threading_mode, tls=False):
+async def _server(interface, port, threading_mode, tls=False, workers=1):
     certs_path = Path.cwd() / "tests" / "fixtures" / "tls"
     tls_opts = (
         f"--ssl-certificate {certs_path / 'cert.pem'} "
@@ -20,6 +20,7 @@ async def _server(interface, port, threading_mode, tls=False):
         "".join([
             f"granian --interface {interface} --port {port} ",
             f"--threads 1 --threading-mode {threading_mode} ",
+            f"--workers {workers} ",
             tls_opts,
             f"tests.apps.{interface}:app"
         ]),

tests/test_lock.py

@@ -0,0 +1,27 @@
+import httpx
+import pytest
+import asyncio
+
+async def make_req(port):
+    async with httpx.AsyncClient() as client:
+        return await client.post(f"http://localhost:{port}/echo", content="test")
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("threading_mode", ["runtime", "workers"])
+@pytest.mark.parametrize("server_mode", ["wsgi", "asgi", "rsgi"])
+async def test_lock(wsgi_server, asgi_server, rsgi_server, threading_mode, server_mode):
+    server = {"wsgi": wsgi_server,
+              "asgi": asgi_server,
+              "rsgi": rsgi_server,
+              }[server_mode]
+    async with server(threading_mode, workers=2) as port:
+        for _ in range(100):
+            ok = 0
+            timeout = 0
+            for res in await asyncio.gather(*[make_req(port) for _ in range(3)], return_exceptions=True):
+                if isinstance(res, Exception):
+                    timeout += 1
+                else:
+                    assert res.status_code == 200
+                    ok += 1
+            assert (timeout, ok) == (0, 3)