ascii_attachments: don't process filename's extension apart

flask_mail.py

@@ -352,11 +352,8 @@ def as_string(self):
             if filename and ascii_attachments:
                 # force filename to ascii
                 filename = unicodedata.normalize('NFKD', filename)
-                filename = filename.encode('ascii', 'ignore')
-                filename, ext = filename.decode('ascii').rsplit(u'.')
-                ext = ext.strip()
-                filename = SPACES.sub(u' ', filename)
-                filename = u'{0}.{1}'.format(filename.strip(), ext)
+                filename = filename.encode('ascii', 'ignore').decode('ascii')
+                filename = SPACES.sub(u' ', filename).strip()
 
             try:
                 filename and filename.encode('ascii')

tests.py

@@ -321,14 +321,13 @@ def test_plain_message_with_ascii_converted_attachment(self):
 
             msg.attach(data=b"this is a test",
                        content_type="text/plain",
-                       filename=u'ünicöde ←→ ✓.txt')
+                       filename=u'ünicödeß ←.→ ✓.txt')
 
             parsed = email.message_from_string(msg.as_string())
             self.assertIn(
-                'Content-Disposition: attachment; filename="unicode.txt"',
+                'Content-Disposition: attachment; filename="unicode . .txt"',
                 msg.as_string())
 
-
     def test_html_message(self):
         html_text = "<p>Hello World</p>"
         msg = Message(sender="from@example.com",