def test_caseInsensitively(self):
        """
        L{searchFileForAll} searches for names case-insensitively.
        """
        hosts = self.path()
        hosts.setContent(b"127.0.0.1     foobar.EXAMPLE.com\n")
        self.assertEqual(
            ["127.0.0.1"], searchFileForAll(hosts, b"FOOBAR.example.com"))

        L{searchFileForAll} searches for names case-insensitively.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_hosts.py