def test_ignoresNonexistantFile(self):
        keydb = checkers.UNIXAuthorizedKeysFiles(self.userdb,
                                                 parseKey=lambda x: x)
        self.assertEqual(self.expectedKeys,
                         list(keydb.getAuthorizedKeys(b'alice')))
L{checkers.UNIXAuthorizedKeysFiles.getAuthorizedKeys} returns only
dataset/ETHPy150Open twisted/twisted/twisted/conch/test/test_checkers.py/UNIXAuthorizedKeysFilesTests.test_ignoresNonexistantFile