import static org.junit.Assert.*;

import org.junit.Test;

public class UTest {

  @Test
  public void testDLListconstructor()
  {
    Solution.DLList list = new Solution.DLList();
    assertEquals(0, list.size());
  }


  @Test
  public void testAddAtZero()
  {
    Solution.DLList list = new Solution.DLList();
    list.addFirst(new Solution.Node(3, null, null));
    list.addLast(new Solution.Node(2, null, null));
    list.addAtPosition(new Solution.Node(5, null, null),0);
    assertEquals(3, list.size());
    Solution.Node node = list.removeFromPosition(10);
    assertNull(node);
    assertEquals(3, list.size());

    assertEquals(3, list.removeFirst().getElement());
    assertEquals(5, list.removeFirst().getElement());

  }
     @Test
    public void addFirstEmpty() {
        Solution.DLList list = new Solution.DLList();

        list.addFirst(new Solution.Node(3, null, null));
        list.addFirst(new Solution.Node(2, null, null));
        list.addFirst(new Solution.Node(1, null, null));


        assertEquals(1, list.removeFirst().getElement());
        assertEquals(2, list.removeFirst().getElement());
        assertEquals(3, list.removeFirst().getElement());
    }

    @Test
    public void reverse() {
        Solution.DLList list = new Solution.DLList();

        list.addFirst(new Solution.Node(3, null, null));
        list.addFirst(new Solution.Node(2, null, null));
        list.addFirst(new Solution.Node(1, null, null));

        list = list.reverse();

        assertEquals(3, list.removeFirst().getElement());
        assertEquals(2, list.removeFirst().getElement());
        assertEquals(1, list.removeFirst().getElement());
    }

    @Test
    public void reverseEmpty() {
        Solution.DLList list = new Solution.DLList();
        list = list.reverse();
        assertEquals(list.size(), 0);
    }

    @Test
    public void addLast() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));
        list.addLast(new Solution.Node(3, null, null));

        assertEquals(1, list.removeFirst().getElement());
        assertEquals(2, list.removeFirst().getElement());
        assertEquals(3, list.removeFirst().getElement());
    }

    @Test
    public void sizeOne() {
        Solution.DLList list = new Solution.DLList();
        list.addLast(new Solution.Node(1, null, null));
        assertEquals(list.size(), 1);
    }

    @Test
    public void sizeThree() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));
        list.addLast(new Sot().getElement());
        assertEquals(99, list.removeFirst().getElement());
        assertEquals(3, list.removeFirst().getElement());
    }

    @Test
    public void addAtPositionLast() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));
        list.addLast(new Solution.Node(3, null, null));

        list.addAtPosition(new Solution.Node(99, null, null), 2);

        assertEquals(1, list.removeFirst().getElement());
        assertEquals(2, list.removeFirst().getElement());
        assertEquals(3, list.removeFirst().getElement());
        assertEquals(99, list.removeFirst().getElement());
    }

    @Test
    public void removeAtPositionOne() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(0, null, null));
        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));

        assertEquals(list.removeFromPosition(1).getElement(), 1);

        assertEquals(0, list.removeFirst().getElement());
        assertEquals(2, list.removeFirst().getElement());
    }

    @Test
    public void removeAtPositionLast() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(0, null, null));
        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));

        assertEquals(list.removeFromPosition(2).getElement(), 2);

        assertEquals(0, list.removeFirst().getElement());
        assertEquals(1, list.removeFirst().getElement());
    }

    @Test
    public void removeAtPositionEmpty() {
        Solution.DLList list = new Solution.DLList();
        list.removeFromPosition(0);
        assertNull(list.removeFromPosition(0));
        assertEquals(list.size(), 0);
    }

    @Test
    public void removeLastFullList() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(0, null, null));
        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));

        assertEquals(list.removeLast().getElement(), 2);

        assertEquals(0, list.removeFirst().getElement());
        assertEquals(1, list.removeFirst().getElement());
    }

    @Test
    public void removeLastEmptyList() {
        Solution.DLList list = new Solution.DLList();
        assertNull(list.removeLast());
    }

    @Test
    public void removeFirstNonEmpty() {
        Solution.DLList list = new Solution.DLList();

        list.addLast(new Solution.Node(0, null, null));
        list.addLast(new Solution.Node(1, null, null));
        list.addLast(new Solution.Node(2, null, null));

        assertNotNull(list.removeFirst().getElement());
        assertEquals(1, list.removeFirst().getElement());
        assertEquals(2, list.removeFirst().getElement());
    }

    @Test
    public void removeFirstEmpty() {
        Solution.DLList list = new Solution.DLList();
        assertNull(list.removeFirst());
    }
}
//import static org.junit.Assert.*;
//
//import org.junit.Test;
//
//public class UTest {
//
//  @Test
//  public void testDLListconstructor()
//  {
//    Solution.DLList list = new Solution.DLList();
//    assertEquals(0, list.size());
//  }
//
//
//  @Test
//  public void testAddAtZero()
//  {
//    Solution.DLList list = new Solution.DLList();
//    list.addFirst(new Solution.Node(3, null, null));
//    list.addLast(new Solution.Node(2, null, null));
//    list.addAtPosition(new Solution.Node(5, null, null),0);
//    assertEquals(3, list.size());
//    Solution.Node node = list.removeFromPosition(10);
//    assertNull