add unit test for Streamable HTTP Trailing Slash Compatibility

Author: chiliu

tests/server/fastmcp/test_server.py

@@ -124,6 +124,22 @@ async def test_starlette_routes_with_mount_path(self):
             mount_routes[0].path == "/messages"
         ), "Mount route path should be /messages"
 
+        mcp = FastMCP()
+        app = mcp.streamable_http_app()
+
+        # Find routes by type
+        streamable_routes = [r for r in app.routes if isinstance(r, Route)]
+        mount_routes = [r for r in app.routes if isinstance(r, Mount)]
+
+        # Verify routes exist
+        assert len(streamable_routes) == 2, "Should have two streamable routes"
+
+        # Verify path values
+        assert streamable_routes[0].path == "/mcp", "Streamable route path should be /mcp"
+        assert streamable_routes[1].path == "/mcp/", "Streamable route path should be /mcp"
+
+
+
     @pytest.mark.anyio
     async def test_non_ascii_description(self):
         """Test that FastMCP handles non-ASCII characters in descriptions correctly"""