def test_lineLength(self):
        """
        Check the length of the lines.
        """
        failures = []
        for line in self.output:
            if not len(line) <= self.lineWidth:
                failures.append(len(line))

        if failures:
            self.fail("%d of %d lines were too long.\n"
                      "%d < %s" % (len(failures), len(self.output),
                                   self.lineWidth, failures))

        Check the length of the lines.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_text.py