diff --git a/pkgs/development/python-modules/pyspcwebgw/default.nix b/pkgs/development/python-modules/pyspcwebgw/default.nix
index bc11a30334da..b847240869ac 100644
--- a/pkgs/development/python-modules/pyspcwebgw/default.nix
+++ b/pkgs/development/python-modules/pyspcwebgw/default.nix
@@ -34,6 +34,10 @@ buildPythonPackage rec {
     pytestCheckHook
   ];
 
+  pytestFlagsArray = [
+    "--asyncio-mode=legacy"
+  ];
+
   pythonImportsCheck = [ "pyspcwebgw" ];
 
   meta = with lib; {