diff --git a/pkgs/development/python-modules/portend/default.nix b/pkgs/development/python-modules/portend/default.nix
index c7c888f6a00e..a8dc0e9907af 100644
--- a/pkgs/development/python-modules/portend/default.nix
+++ b/pkgs/development/python-modules/portend/default.nix
@@ -1,5 +1,5 @@
 { stdenv, buildPythonPackage, fetchPypi
-, pytest, setuptools_scm, tempora, pytest-flake8 }:
+, pytest, setuptools_scm, tempora }:
 
 buildPythonPackage rec {
   pname = "portend";
@@ -10,11 +10,15 @@ buildPythonPackage rec {
     sha256 = "b7ce7d35ea262415297cbfea86226513e77b9ee5f631d3baa11992d663963719";
   };
 
+  postPatch = ''
+    substituteInPlace pytest.ini --replace "--flake8" ""
+  '';
+
   nativeBuildInputs = [ setuptools_scm ];
 
   propagatedBuildInputs = [ tempora ];
 
-  checkInputs = [ pytest pytest-flake8 ];
+  checkInputs = [ pytest ];
 
   checkPhase = ''
     py.test