diff --git a/pkgs/development/python-modules/blessed/default.nix b/pkgs/development/python-modules/blessed/default.nix
index 2d1ac11f3b5..d3ea1f151d3 100644
--- a/pkgs/development/python-modules/blessed/default.nix
+++ b/pkgs/development/python-modules/blessed/default.nix
@@ -1,4 +1,5 @@
-{ stdenv, buildPythonPackage, fetchPypi, six, wcwidth }:
+{ stdenv, buildPythonPackage, fetchPypi, six, wcwidth, pytest, mock
+, glibcLocales }:
 
 buildPythonPackage rec {
   name = "${pname}-${version}";
@@ -10,6 +11,12 @@ buildPythonPackage rec {
     sha256 = "0fv9f0074kxy1849h0kwwxw12sifpq3bv63pcz900zzjsigi4hi3";
   };
 
+  checkInputs = [ pytest mock glibcLocales ];
+
+  checkPhase = ''
+    LANG=en_US.utf-8 py.test blessed/tests
+  '';
+
   propagatedBuildInputs = [ wcwidth six ];
 
   meta = with stdenv.lib; {