diff --git a/pkgs/development/python-modules/fixtures/default.nix b/pkgs/development/python-modules/fixtures/default.nix
index 9f1549e98f9..43e849415c0 100644
--- a/pkgs/development/python-modules/fixtures/default.nix
+++ b/pkgs/development/python-modules/fixtures/default.nix
@@ -17,7 +17,17 @@ buildPythonPackage rec {
     sha256 = "fcf0d60234f1544da717a9738325812de1f42c2fa085e2d9252d8fff5712b2ef";
   };
 
-  propagatedBuildInputs = [ pbr testtools mock ];
+  nativeBuildInputs = [
+    pbr
+  ];
+
+  propagatedBuildInputs = [
+    testtools
+  ];
+
+  checkInputs = [
+    mock
+  ];
 
   checkPhase = ''
     ${python.interpreter} -m testtools.run fixtures.test_suite