diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 061f2683dc7e..4cac581d20ce 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -3975,18 +3975,13 @@ in modules // {
 
   decorator = buildPythonPackage rec {
     name = "decorator-${version}";
-    version = "4.0.4";
+    version = "4.0.6";
 
     src = pkgs.fetchurl {
       url = "http://pypi.python.org/packages/source/d/decorator/${name}.tar.gz";
-      sha256 = "1qf3iiv401vhsdmf4bd08fwb3fq4xq769q2yl7zqqr1iml7w3l2s";
+      sha256 = "1c6254597777fd003da2e8fb503c3dbf3d9e8f8d55f054709c0e65be3467209c";
     };
 
-    # no idea what that file is doing there (probably bad release)
-    preCheck = ''
-      rm src/tests/x.py
-    '';
-
     meta = {
       homepage = http://pypi.python.org/pypi/decorator;
       description = "Better living through Python with decorators";
@@ -19138,12 +19133,15 @@ in modules // {
     buildInputs = with self; [ nose coverage pkgs.glibcLocales flake8 ];
     propagatedBuildInputs = with self; [ matplotlib pandas ];
 
+    # Performance test fails
+    prePatch = ''
+      rm tqdm/tests/tests_perf.py
+    '';
+
     preBuild = ''
       export LC_ALL="en_US.UTF-8"
     '';
 
-    doCheck = !(isPy27); # Performance test fails
-
     meta = {
       description = "A Fast, Extensible Progress Meter";
       homepage = https://github.com/tqdm/tqdm;