@Test
    public void testClear() throws Exception {
        map.clear();
        assertThat(map.size(), is(0));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testEntrySet() throws Exception {
        Iterator<Map.Entry<String, String>> i = map.entrySet().iterator();
        assertThat(i.next().getKey(), is(nullValue()));
        assertThat(i.next().getKey(), is("1"));