def test_formatRootTagWithFilename(self):
        """
        The C{_formatRoot} method formats a C{Tag} with filename information
        using the filename, line, column, and tag information
        """
        e = self.makeFlattenerError()
        t = Tag('a-tag', filename='tpl.py', lineNumber=10, columnNumber=20)
        self.assertEqual(e._formatRoot(t),
                         'File "tpl.py", line 10, column 20, in "a-tag"')

        The C{_formatRoot} method formats a C{Tag} with filename information
        using the filename, line, column, and tag information
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_error.py