for (int i = 0; i < nestingDepth; i++) {
      iterator = Iterators.concat(iterator, iterateOver(1));
    }
    assertEquals(nestingDepth, Iterators.size(iterator));
  }

  public void testConcatNested_appendToBeginning() {
    int nestingDepth = 128;
    Iterator<Integer> iterator = iterateOver();
    for (int i = 0; i < nestingDepth; i++) {
      iterator = Iterators.concat(iterateOver(1), iterator);
    }