👷 Add new memory benchmark (#16064)

tests/memory_benchmarks/test_route_dependency_graph.py

@@ -0,0 +1,64 @@
+import sys
+from collections.abc import Callable
+from typing import Annotated, Any
+
+import pytest
+from fastapi import Depends, FastAPI
+from fastapi.routing import APIRoute
+
+if "--codspeed" not in sys.argv:
+    pytest.skip(
+        "Benchmark tests are skipped by default; run with --codspeed.",
+        allow_module_level=True,
+    )
+
+LAST_DEPENDENCY_INDEX = 100
+ROUTE_COUNT = 20
+ROUTE_PATH_PREFIX = "/route-"
+
+
+def _create_app() -> FastAPI:
+    app = FastAPI()
+    dependencies: dict[int, Callable[..., Any]] = {}
+
+    def create_dependency(index: int) -> Callable[..., Any]:
+        if index == LAST_DEPENDENCY_INDEX:
+
+            def dependency() -> str:
+                return str(index)
+
+            dependency.__name__ = f"dependency_{index}"
+            return dependency
+
+        next_dependency = dependencies[index + 1]
+
+        async def dependency(
+            sub_dependency: Annotated[str, Depends(next_dependency)],
+        ) -> str:
+            return f"{index} -> {sub_dependency}"
+
+        dependency.__name__ = f"dependency_{index}"
+        return dependency
+
+    for index in reversed(range(LAST_DEPENDENCY_INDEX + 1)):
+        dependencies[index] = create_dependency(index)
+
+    async def endpoint(
+        value: Annotated[str, Depends(dependencies[0])],
+    ) -> dict[str, str]:
+        return {"value": value}
+
+    for index in range(ROUTE_COUNT):
+        app.add_api_route(f"{ROUTE_PATH_PREFIX}{index}", endpoint)
+
+    return app
+
+
+def test_route_dependency_graph(benchmark) -> None:
+    app = benchmark(_create_app)
+    api_routes = [
+        route
+        for route in app.routes
+        if isinstance(route, APIRoute) and route.path.startswith(ROUTE_PATH_PREFIX)
+    ]
+    assert len(api_routes) == ROUTE_COUNT