diff --git a/pkgs/development/python-modules/async-lru/default.nix b/pkgs/development/python-modules/async-lru/default.nix
index 9dc412ccde86..69e6519b32c3 100644
--- a/pkgs/development/python-modules/async-lru/default.nix
+++ b/pkgs/development/python-modules/async-lru/default.nix
@@ -28,6 +28,10 @@ buildPythonPackage rec {
     pytest-asyncio
   ];
 
+  pytestFlagsArray = [
+    "--asyncio-mode=strict"
+  ];
+
   disabledTests = [
     # https://github.com/aio-libs/async-lru/issues/341
     "test_alru_cache_deco"