def test_identity(self):
   self.assertEqual(
     data_urlparse(data_urlencode(png, b('image/png'), charset=None)),
     (png, (b('image'), b('png'), {}))
   )
   self.assertEqual(
     data_urlparse(data_urlencode(png, b('image/png'),
                                  charset=None, encoder=None)),
     (png, (b('image'), b('png'), {}))
   )
  def test_encoding(self):
    self.assertEqual(data_urlencode(png, b('image/png'), charset=None),
                     png_data_url)
    self.assertEqual(data_urlencode(png, b('image/png'),
                                    charset=None, encoder=None),
                     png_data_url_quoted)

    self.assertEqual(data_urlencode(rfc_gif, b('image/gif'),
                                    charset=None),
                     rfc_gif_data_url)
    #        self.assertEqual(dataurl_encode(rfc_gif, b('image/gif'),
    #                                        charset=None),
    #                         rfc_gif_data_url_quoted)
    self.assertEqual(data_urlencode(b('A brief note'),
                                    b(''),
                                    b(''), None), rfc_note_data_url)