Run StreamableHTTP transport tests in process instead of over sockets (#2767)

src/mcp/server/streamable_http.py

@@ -207,7 +207,7 @@ class StreamableHTTPServerTransport:
             send_stream.close()
             receive_stream.close()
 
-    def close_standalone_sse_stream(self) -> None:  # pragma: no cover
+    def close_standalone_sse_stream(self) -> None:
         """Close the standalone GET SSE stream, triggering client reconnection.
 
         This method closes the HTTP connection for the standalone GET stream used
@@ -221,8 +221,6 @@ class StreamableHTTPServerTransport:
             This is a no-op if there is no active standalone SSE stream.
             Requires event_store to be configured for events to be stored during
             the disconnect.
-            Currently, client reconnection for standalone GET streams is NOT
-            implemented - this is a known gap (see test_standalone_get_stream_reconnection).
         """
         self.close_sse_stream(GET_STREAM_KEY)
 
@@ -245,7 +243,7 @@ class StreamableHTTPServerTransport:
             async def close_stream_callback() -> None:
                 self.close_sse_stream(request_id)
 
-            async def close_standalone_stream_callback() -> None:  # pragma: no cover
+            async def close_standalone_stream_callback() -> None:
                 self.close_standalone_sse_stream()
 
             metadata = ServerMessageMetadata(
@@ -421,7 +419,7 @@ class StreamableHTTPServerTransport:
         has_json, has_sse = self._check_accept_headers(request)
         if self.is_json_response_enabled:
             # For JSON-only responses, only require application/json
-            if not has_json:  # pragma: no cover
+            if not has_json:
                 response = self._create_error_response(
                     "Not Acceptable: Client must accept application/json",
                     HTTPStatus.NOT_ACCEPTABLE,

tests/test_helpers.py

@@ -2,7 +2,6 @@
 
 import socket
 import threading
-import time
 from collections.abc import Generator
 from contextlib import contextmanager
 from typing import Any
@@ -56,30 +55,3 @@ def run_uvicorn_in_thread(app: Any, **config_kwargs: Any) -> Generator[str, None
     finally:
         server.should_exit = True
         thread.join(timeout=_SERVER_SHUTDOWN_TIMEOUT_S)
-
-
-def wait_for_server(port: int, timeout: float = 20.0) -> None:
-    """Wait for server to be ready to accept connections.
-
-    Polls the server port until it accepts connections or timeout is reached.
-    This eliminates race conditions without arbitrary sleeps.
-
-    Args:
-        port: The port number to check
-        timeout: Maximum time to wait in seconds (default 5.0)
-
-    Raises:
-        TimeoutError: If server doesn't start within the timeout period
-    """
-    start_time = time.time()
-    while time.time() - start_time < timeout:
-        try:
-            with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
-                s.settimeout(0.1)
-                s.connect(("127.0.0.1", port))
-                # Server is ready
-                return
-        except (ConnectionRefusedError, OSError):
-            # Server not ready yet, retry quickly
-            time.sleep(0.01)
-    raise TimeoutError(f"Server on port {port} did not start within {timeout} seconds")  # pragma: no cover