def load(self, requirements_file=None):
        """Load or reload requirements from a requirements.txt file.

        :param requirements_file: if not given, the filename used from
            initialization will be read again.
        """
        if requirements_file is None:
            requirements_file = self.filename
            if requirements_file is None:
                raise ValueError("no filename provided")
        elif isinstance(requirements_file, text_type):
            requirements_file = Path(requirements_file)
        self.clear()
        with requirements_file.open() as f:
            self.loads(f.read())

        if isinstance(requirements_file, (text_type, Path)):
            self.filename = requirements_file
def test_rule_300(self):
        oRule = iteration_scheme.rule_300()
        self.assertTrue(oRule)
        self.assertEqual(oRule.name, 'iteration_scheme')
        self.assertEqual(oRule.identifier, '300')

        lExpected = [13, 17]

        oRule.analyze(self.oFile)
        self.assertEqual(lExpected, utils.extract_violation_lines_from_violation_object(oRule.violations))