def test_defaultCheckers(self):
        """
        L{UNIXPasswordDatabase} with no arguments has checks the C{pwd} database
        and then the C{spwd} database.
        """
        checker = checkers.UNIXPasswordDatabase()

        def crypted(username, password):
            salt = crypt.crypt(password, username)
            crypted = crypt.crypt(password, '$1$' + salt)
            return crypted

        pwd = UserDatabase()
        pwd.addUser('alice', crypted('alice', 'password'),
                    1, 2, 'foo', '/foo', '/bin/sh')
        # x and * are convention for "look elsewhere for the password"
        pwd.addUser('bob', 'x', 1, 2, 'bar', '/bar', '/bin/sh')
        spwd = ShadowDatabase()
        spwd.addUser('alice', 'wrong', 1, 2, 3, 4, 5, 6, 7)
        spwd.addUser('bob', crypted('bob', 'password'),
                     8, 9, 10, 11, 12, 13, 14)

        self.patch(checkers, 'pwd', pwd)
        self.patch(checkers, 'spwd', spwd)

        mockos = MockOS()
        self.patch(util, 'os', mockos)

        mockos.euid = 2345
        mockos.egid = 1234

        cred = UsernamePassword(b"alice", b"password")
        self.assertLoggedIn(checker.requestAvatarId(cred), b'alice')
        self.assertEqual(mockos.seteuidCalls, [])
        self.assertEqual(mockos.setegidCalls, [])
        cred.username = b"bob"
        self.assertLoggedIn(checker.requestAvatarId(cred), b'bob')
        self.assertEqual(mockos.seteuidCalls, [0, 2345])
        self.assertEqual(mockos.setegidCalls, [0, 1234])

        L{UNIXPasswordDatabase} with no arguments has checks the C{pwd} database
        and then the C{spwd} database.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_checkers.py