diff --git a/pkgs/development/python-modules/oschmod/default.nix b/pkgs/development/python-modules/oschmod/default.nix
index 8ce9b703c6b2..e724623d1d90 100644
--- a/pkgs/development/python-modules/oschmod/default.nix
+++ b/pkgs/development/python-modules/oschmod/default.nix
@@ -3,6 +3,8 @@
   buildPythonPackage,
   fetchPypi,
   setuptools,
+  mock,
+  pytest-mock,
   pytestCheckHook,
 }:
 
@@ -18,7 +20,11 @@ buildPythonPackage rec {
 
   build-system = [ setuptools ];
 
-  nativeCheckInputs = [ pytestCheckHook ];
+  nativeCheckInputs = [
+    mock
+    pytest-mock
+    pytestCheckHook
+  ];
 
   pythonImportsCheck = [ "oschmod" ];