@Test
public void dictsToTrie_nonnull_should_return_trie() throws Exception {

    List<PinyinDict> dicts = new ArrayList<PinyinDict>();
    dicts.add(new PinyinMapDict() {
        @Override
        public Map<String, String[]> mapping() {
            Map<String, String[]> map = new HashMap<String, String[]>();
            map.put("1", null);
            return map;
        }
    });
    assertThat(Utils.dictsToTrie(dicts), notNullValue());
}