Задачи | 7 уровень | 4 лекция

import com.javarush.task.task37.task3701.Solution;
import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

import java.util.ArrayList;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.NoSuchElementException;


public class SolutionTest {
    private Solution<Integer> list;

    @Before
    public void setUp() {
        list = new Solution<>();
        list.add(1);
        list.add(2);
        list.add(3);
    }

    @Test
    public void testRoundIterator() {
        Iterator<Integer> iterator = list.iterator();
        Integer[] expected = {1, 2, 3, 1, 2, 3, 1, 2, 3, 1};
        int count = 0;
        try {
            for (Integer integer : expected) {
                assertEquals(integer, iterator.next());
                count++;
                if (count == 10) {
                    break;
                }
            }
        } catch (NoSuchElementException e) {
            fail("NoSuchElementException was thrown");
        }
    }

    @Test
    public void testRemove() {
        Iterator<Integer> iterator = list.iterator();
        iterator.next();
        iterator.remove();

        assertFalse(list.contains(1));
        assertEquals(2, list.size());
    }

    @Test(expected = ConcurrentModificationException.class)
    public void testConcurrentModification() {
        Iterator<Integer> iterator = list.iterator();
        list.add(4);
        iterator.next();
    }

    @Test
    public void testIteratorType() {
        Iterator<Integer> iterator = list.iterator();
        assertTrue(iterator instanceof Solution.RoundIterator);
    }

    @Test
    public void testSolutionExtendedArrayList() {
        Solution<Integer> solution = new Solution<>();
        assertTrue(solution instanceof ArrayList);
    }
}

@Override
    public Iterator<T> iterator() {
        return new RoundIterator(0);
    }

 public class RoundIterator implements Iterator<T>

  while (it.hasPrevious())
                {
                    it.previous();
                }