use event in test_messages_are_executed_concurrently

Author: ihrpr

tests/issues/test_188_concurrency.py

@@ -5,45 +5,39 @@
 from mcp.server.fastmcp import FastMCP
 from mcp.shared.memory import create_connected_server_and_client_session as create_session
 
-_sleep_time_seconds = 0.01
 _resource_name = "slow://slow_resource"
 
 
-@pytest.mark.filterwarnings(
-    "ignore:coroutine 'test_messages_are_executed_concurrently.<locals>.slow_resource' was never awaited:RuntimeWarning"
-)
 @pytest.mark.anyio
 async def test_messages_are_executed_concurrently():
     server = FastMCP("test")
-    call_timestamps = []
+    event = anyio.Event()
+    call_order = []
 
     @server.tool("sleep")
     async def sleep_tool():
-        call_timestamps.append(("tool_start_time", anyio.current_time()))
-        await anyio.sleep(_sleep_time_seconds)
-        call_timestamps.append(("tool_end_time", anyio.current_time()))
+        call_order.append("waiting_for_event")
+        await event.wait()
+        call_order.append("tool_end")
         return "done"
 
     @server.resource(_resource_name)
     async def slow_resource():
-        call_timestamps.append(("resource_start_time", anyio.current_time()))
-        await anyio.sleep(_sleep_time_seconds)
-        call_timestamps.append(("resource_end_time", anyio.current_time()))
+        event.set()
+        call_order.append("resource_end")
         return "slow"
 
     async with create_session(server._mcp_server) as client_session:
+        # First tool will wait on event, second will set it
         async with anyio.create_task_group() as tg:
-            for _ in range(10):
-                tg.start_soon(client_session.call_tool, "sleep")
-                tg.start_soon(client_session.read_resource, AnyUrl(_resource_name))
-
-        active_calls = 0
-        max_concurrent_calls = 0
-        for call_type, _ in sorted(call_timestamps, key=lambda x: x[1]):
-            if "start" in call_type:
-                active_calls += 1
-                max_concurrent_calls = max(max_concurrent_calls, active_calls)
-            else:
-                active_calls -= 1
-        print(f"Max concurrent calls: {max_concurrent_calls}")
-        assert max_concurrent_calls > 1, "No concurrent calls were executed"
+            # Start the tool first (it will wait on event)
+            tg.start_soon(client_session.call_tool, "sleep")
+            # Then the resource (it will set the event)
+            tg.start_soon(client_session.read_resource, AnyUrl(_resource_name))
+
+        # Verify that both ran concurrently
+        assert call_order == [
+            "waiting_for_event",
+            "resource_end",
+            "tool_end",
+        ], f"Expected concurrent execution, but got: {call_order}"