map.put("3", null);
        assertThat(map.containsKey("3"), is(true));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testIndexOf() throws Exception {
        assertThat(map.indexOf("test"), is(1));
        assertThat(map.indexOf(null), is(0));
        assertThat(map.indexOf("test3"), is(-1));
    }

    /**
     * @throws Exception

        assertThat(newArray.length, is(2));
        assertThat(newArray[0], is(1));
        assertThat(newArray[1], is(2));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testIndexOf() throws Exception {
        final String[] array = new String[] { "111", "222", "333", "222" };
        assertThat(ArrayUtil.indexOf(array, "222"), is(1));
        assertThat(ArrayUtil.indexOf(array, "222", 2), is(3));