fix _flatten_to_ascii for str inputs

common/djangoapps/external_auth/tests/test_shib.py

@@ -514,8 +514,16 @@ class ShibUtilFnTest(TestCase):
     """
     def test__flatten_to_ascii(self):
         DIACRITIC = u"àèìòùÀÈÌÒÙáéíóúýÁÉÍÓÚÝâêîôûÂÊÎÔÛãñõÃÑÕäëïöüÿÄËÏÖÜŸåÅçÇ"  # pylint: disable=C0103
+        STR_DIACRI = "àèìòùÀÈÌÒÙáéíóúýÁÉÍÓÚÝâêîôûÂÊÎÔÛãñõÃÑÕäëïöüÿÄËÏÖÜŸåÅçÇ"  # pylint: disable=C0103
         FLATTENED = u"aeiouAEIOUaeiouyAEIOUYaeiouAEIOUanoANOaeiouyAEIOUYaAcC"  # pylint: disable=C0103
         self.assertEqual(_flatten_to_ascii(u'jas\xf6n'), u'jason')  # umlaut
         self.assertEqual(_flatten_to_ascii(u'Jason\u5305'), u'Jason')  # mandarin, so it just gets dropped
         self.assertEqual(_flatten_to_ascii(u'abc'), u'abc')  # pass through
-        self.assertEqual(_flatten_to_ascii(DIACRITIC), FLATTENED)
+
+        unicode_test = _flatten_to_ascii(DIACRITIC)
+        self.assertEqual(unicode_test, FLATTENED)
+        self.assertIsInstance(unicode_test, unicode)
+
+        str_test = _flatten_to_ascii(STR_DIACRI)
+        self.assertEqual(str_test, FLATTENED)
+        self.assertIsInstance(str_test, str)

common/djangoapps/external_auth/views.py

@@ -233,10 +233,13 @@ def _flatten_to_ascii(txt):
     """
     Flattens possibly unicode txt to ascii (django username limitation)
     @param name:
-    @return:
+    @return: the flattened txt (in the same type as was originally passed in)
     """
-    return unicodedata.normalize('NFKD', txt).encode('ASCII', 'ignore')
-
+    if isinstance(txt, str):
+        txt = txt.decode('utf-8')
+        return unicodedata.normalize('NFKD', txt).encode('ASCII', 'ignore')
+    else:
+        return unicode(unicodedata.normalize('NFKD', txt).encode('ASCII', 'ignore'))
 
 @ensure_csrf_cookie
 @cache_if_anonymous