@Test
public void whenConvertDataFromIteratorIteratorovThatGetSimpleIterator(){

    ArrayList<Integer> one = new ArrayList<>(Arrays.asList(4,2,0,4,6,4,9));
    ArrayList<Integer> two = new ArrayList<>(Arrays.asList(0,9,8,7,5));
    ArrayList<Integer> three = new ArrayList<>(Arrays.asList(1,3,5,6,7,0,9,8,4));
    ArrayList<Iterator<Integer>> bigBox = new ArrayList<>(Arrays.asList(one.iterator(),two.iterator(),three.iterator()));
    ConvertIterator converter = new ConvertIterator();
    Iterator<Integer> it = converter.convert(bigBox.iterator());
    int[] control = {4,2,0,4,6,4,9,0,9,8,7,5,1,3,5,6,7,0,9,8,4};
    int[] result = new int[21];
    int position = 0;
    while(it.hasNext()){
        result[position++] = it.next();
    }
    Assert.assertThat(result,is(control));
}