diff --git a/pkgs/development/python-modules/kazoo/default.nix b/pkgs/development/python-modules/kazoo/default.nix
index 06ddce72862c..2c3f84bc2bc7 100644
--- a/pkgs/development/python-modules/kazoo/default.nix
+++ b/pkgs/development/python-modules/kazoo/default.nix
@@ -2,6 +2,11 @@
   lib,
   buildPythonPackage,
   fetchPypi,
+
+  # optional dependencies
+  eventlet,
+  gevent,
+  pure-sasl,
 }:
 
 buildPythonPackage rec {
@@ -14,6 +19,17 @@ buildPythonPackage rec {
     hash = "sha256-kFeWrk9MEr1OSukubl0BhDnmtWyM+7JIJTYuebIw2rE=";
   };
 
+  optional-dependencies = {
+    eventlet = [ eventlet ];
+    gevent = [ gevent ];
+    sasl = [ pure-sasl ];
+  };
+
+  pythonImportsCheck = [
+    "kazoo"
+    "kazoo.client"
+  ];
+
   # tests take a long time to run and leave threads hanging
   doCheck = false;
 
diff --git a/pkgs/development/python-modules/pure-sasl/default.nix b/pkgs/development/python-modules/pure-sasl/default.nix
index 6e76ecb7dd61..e7f339d0e9aa 100644
--- a/pkgs/development/python-modules/pure-sasl/default.nix
+++ b/pkgs/development/python-modules/pure-sasl/default.nix
@@ -2,7 +2,15 @@
   lib,
   buildPythonPackage,
   fetchFromGitHub,
+
+  # build system
+  setuptools,
+
+  # optional dependencies
   pykerberos,
+
+  # test dependencies
+  mock,
   pytestCheckHook,
   six,
 }:
@@ -10,7 +18,7 @@
 buildPythonPackage rec {
   pname = "pure-sasl";
   version = "0.6.2";
-  format = "setuptools";
+  pyproject = true;
 
   src = fetchFromGitHub {
     owner = "thobbs";
@@ -19,23 +27,29 @@ buildPythonPackage rec {
     hash = "sha256-AHoZ3QZLr0JLE8+a2zkB06v2wRknxhgm/tcEPXaJX/U=";
   };
 
-  postPatch = ''
-    substituteInPlace tests/unit/test_mechanism.py \
-      --replace 'from mock import patch' 'from unittest.mock import patch'
-  '';
+  build-system = [ setuptools ];
 
-  pythonImportsCheck = [ "puresasl" ];
+  optional-dependencies = {
+    gssapi = [ pykerberos ];
+  };
+
+  pythonImportsCheck = [
+    "puresasl"
+    "puresasl.client"
+    "puresasl.mechanisms"
+  ];
 
   nativeCheckInputs = [
-    pykerberos
+    mock
     pytestCheckHook
     six
-  ];
+  ]
+  ++ lib.concatAttrValues optional-dependencies;
 
   meta = {
     description = "Reasonably high-level SASL client written in pure Python";
     homepage = "http://github.com/thobbs/pure-sasl";
-    changelog = "https://github.com/thobbs/pure-sasl/blob/0.6.2/CHANGES.rst";
+    changelog = "https://github.com/thobbs/pure-sasl/blob/${src.tag}/CHANGES.rst";
     license = lib.licenses.mit;
     maintainers = with lib.maintainers; [ jherland ];
   };