def METHOD_NAME(self):
    """Adapted from Sennrich et al. 2015 and https://github.com/rsennrich/subword-nmt"""
    tokenizer = FSMTTokenizer(self.langs, self.src_vocab_file, self.tgt_vocab_file, self.merges_file)
    text = "lower"
    bpe_tokens = ["low", "er</w>"]
    tokens = tokenizer.tokenize(text)
    self.assertListEqual(tokens, bpe_tokens)
    input_tokens = tokens + ["<unk>"]
    input_bpe_tokens = [14, 15, 20]
    self.assertListEqual(tokenizer.convert_tokens_to_ids(input_tokens), input_bpe_tokens)