Fix UTF-8 test case for all Python versions.

test/TodoFileTest.py

-#-*- coding: utf-8 -*-
-
 # Topydo - A todo.txt client written in Python.
 # Copyright (C) 2014 Bram Schoenmakers <me@bramschoenmakers.nl>
 #
@@ -16,6 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+from six import u
 import unittest
 
 from test.TestFacilities import load_file
@@ -30,7 +29,7 @@ class TodoFileTest(TopydoTest):
     def test_utf_8(self):
         todofile = load_file('test/data/utf-8.txt')
 
-        self.assertEqual(todofile[0].source(), u'(C) ► UTF-8 test ◄' )
+        self.assertEqual(todofile[0].source(), u('(C) \u25ba UTF-8 test \u25c4'))
 
 if __name__ == '__main__':
     unittest.main()