diff --git a/pkgs/development/python-modules/testfixtures/default.nix b/pkgs/development/python-modules/testfixtures/default.nix
index a1d791306cc1..911d1496165f 100644
--- a/pkgs/development/python-modules/testfixtures/default.nix
+++ b/pkgs/development/python-modules/testfixtures/default.nix
@@ -6,6 +6,7 @@
 , pytestCheckHook
 , pythonAtLeast
 , pythonOlder
+, setuptools
 , sybil
 , twisted
 , zope-component
@@ -14,7 +15,7 @@
 buildPythonPackage rec {
   pname = "testfixtures";
   version = "7.2.2";
-  format = "setuptools";
+  pyproject = true;
   # DO NOT CONTACT upstream.
   # https://github.com/simplistix/ is only concerned with internal CI process.
   # Any attempt by non-standard pip workflows to comment on issues will
@@ -38,6 +39,10 @@ buildPythonPackage rec {
      })
   ];
 
+  nativeBuildInputs = [
+    setuptools
+  ];
+
   nativeCheckInputs = [
     mock
     pytestCheckHook