def _test_external_url(self, url, expected_url): with mock.patch.object(Pynliner, '_get_url') as mocked: def check_url(url): self.assertEqual(url, expected_url) return ".b1,.b2 { font-weight:bold; } .c {color: red}" mocked.side_effect = check_url p = Pynliner() p.root_url = self.root_url p.relative_url = self.relative_url p.from_string(self.html_template.format(href=url)) p._get_soup() p._get_styles()