Make tests/text_quotations_test.py compatible with Python 3.

tests/text_quotations_test.py

@@ -10,6 +10,7 @@ import email.iterators
 from talon import quotations
 import six
 from six.moves import range
+from six import StringIO
 
 
 @patch.object(quotations, 'MAX_LINES_COUNT', 1)
@@ -665,6 +666,15 @@ def test_preprocess_postprocess_2_links():
     eq_(msg_body, quotations.extract_from_plain(msg_body))
 
 
+def body_iterator(msg, decode=False):
+    for subpart in msg.walk():
+        payload = subpart.get_payload(decode=decode)
+        if isinstance(payload, six.text_type):
+            yield payload
+        else:
+            yield payload.decode('utf8')
+
+
 def test_standard_replies():
     for filename in os.listdir(STANDARD_REPLIES):
         filename = os.path.join(STANDARD_REPLIES, filename)
@@ -673,7 +683,7 @@ def test_standard_replies():
         with open(filename) as f:
             message = email.message_from_file(f)
             body = next(email.iterators.typed_subpart_iterator(message, subtype='plain'))
-            text = ''.join(email.iterators.body_line_iterator(body, True))
+            text = ''.join(body_iterator(body, True))
 
             stripped_text = quotations.extract_from_plain(text)
             reply_text_fn = filename[:-4] + '_reply_text'