diff --git a/pkgs/development/python-modules/caldav/default.nix b/pkgs/development/python-modules/caldav/default.nix
index d577264a4880..97a2e3baf5b2 100644
--- a/pkgs/development/python-modules/caldav/default.nix
+++ b/pkgs/development/python-modules/caldav/default.nix
@@ -11,6 +11,7 @@
 , setuptools
 , tzlocal
 , vobject
+, xandikos
 }:
 
 buildPythonPackage rec {
@@ -43,15 +44,9 @@ buildPythonPackage rec {
 
   nativeCheckInputs = [
     pytestCheckHook
+    xandikos
   ];
 
-  # xandikos and radicale are only optional test dependencies, not available for python3
-  postPatch = ''
-    substituteInPlace setup.py \
-      --replace xandikos "" \
-      --replace radicale ""
-  '';
-
   pythonImportsCheck = [ "caldav" ];
 
   meta = with lib; {