modelcontextprotocol · ihrpr · Jul 18, 2025 · Jul 18, 2025 · Jul 18, 2025
diff --git a/tests/issues/test_88_random_error.py b/tests/issues/test_88_random_error.py
@@ -28,8 +28,7 @@ async def test_notification_validation_error(tmp_path: Path):

    server = Server(name="test")
    request_count = 0
-    slow_request_started = anyio.Event()
-    slow_request_complete = anyio.Event()
+    slow_request_lock = anyio.Event()

    @server.list_tools()
    async def list_tools() -> list[types.Tool]:
@@ -52,16 +51,9 @@ async def slow_tool(name: str, arg) -> Sequence[ContentBlock]:
        request_count += 1

        if name == "slow":
-            # Signal that slow request has started
-            slow_request_started.set()
-            # Long enough to ensure timeout
-            await anyio.sleep(0.2)
-            # Signal completion
-            slow_request_complete.set()
+            await slow_request_lock.wait()  # it should timeout here
            return [TextContent(type="text", text=f"slow {request_count}")]
        elif name == "fast":
-            # Fast enough to complete before timeout
-            await anyio.sleep(0.01)
            return [TextContent(type="text", text=f"fast {request_count}")]
        return [TextContent(type="text", text=f"unknown {request_count}")]

@@ -90,16 +82,15 @@ async def client(read_stream, write_stream, scope):
            # First call should work (fast operation)
            result = await session.call_tool("fast")
            assert result.content == [TextContent(type="text", text="fast 1")]
-            assert not slow_request_complete.is_set()
+            assert not slow_request_lock.is_set()

            # Second call should timeout (slow operation)
            with pytest.raises(McpError) as exc_info:
                await session.call_tool("slow")
            assert "Timed out while waiting" in str(exc_info.value)

-            # Wait for slow request to complete in the background
-            with anyio.fail_after(1):  # Timeout after 1 second
-                await slow_request_complete.wait()
+            # release the slow request not to have hanging process
+            slow_request_lock.set()

            # Third call should work (fast operation),
            # proving server is still responsive