def test_word_known(self):
        """ test if the word is a `known` word or not """
        self.assertEqual(spell.known(['this']), {'this'})
        self.assertEqual(spell.known(['hi']), {'hi'})
        self.assertEqual(spell.known(['holmes']), {'holmes'})
        self.assertEqual(spell.known(['known']), {'known'})

        self.assertEqual(spell.known(['-']), set())
        self.assertEqual(spell.known(['foobar']), set())
        self.assertEqual(spell.known(['ths']), set())
        self.assertEqual(spell.known(['ergos']), set())
 test if the word is a `known` word or not 
tests/en_spell_dict_test.py