unit tests

import static org.junit.Assert.*;

import org.junit.Test;

public class UTest {

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

  //addFirst()/addLast()
  @Test
  public void testAddLastAndFirst(){
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(103,null,null));
    list.addFirst(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(104,null,null));
    list.addFirst(new Solution.Node(101,null,null));
    assertEquals(101, list.getHead().getNext().getElement());
    assertEquals(102, list.getHead().getNext().getNext().getElement());
    assertEquals(103, list.getHead().getNext().getNext().getNext().getElement());
    assertEquals(104, list.getHead().getNext().getNext().getNext().getNext().getElement());
  }

  @Test
  public void testAddFirstSize() {
    Solution.DLList list = new Solution.DLList();
    list.addFirst(new Solution.Node(101,null,null));
    assertEquals(1, list.size());
  }

  @Test
  public void testAddLastContent(){
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    assertEquals(101, list.getHead().getNext().getElement());
  }

  //removeFirst()/removeLast()
  public void testRemoveLastEmpty(){
    Solution.DLList list = new Solution.DLList();
    Solution.Node remove = list.removeLast();
    assertEquals(null, remove);
  }

  @Test
  public void testRemoveLastReturn(){
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(107, null, null));
    Solution.Node remove = list.removeLast();
    assertEquals(107, remove.getElement());
  }

  @Test
  public void testRemoveLastSize() {
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addLast(new Solution.Node(104,null,null));
    list.removeLast();
    assertEquals(3, list.size());
  }

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

  @Test
  public void testSizeOne(){
    Solution.DLList list = new Solution.DLList();
    list.addFirst(new Solution.Node(101,null,null));
    assertEquals(1, list.size());
  }

  @Test
  public void testSizeMultiple(){
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addLast(new Solution.Node(104,null,null));
    assertEquals(4, list.size());
  }

  //addAtPositon()
  @Test
  public void testAddAtPositionNegative(){
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addAtPosition(new Solution.Node(102,null,null), -3);
    assertEquals(102, list.getHead().getNext().getNext().getElement());
    assertEquals(2, list.size());
  }

  @Test
  public void testAddAtPositionOnList() {
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addLast(new Solution.Node(104,null,null));
    list.addAtPosition(new Solution.Node(102,null,null), 1);
    assertEquals(102, list.getHead().getNext().getNext().getElement());
  }

  @Test
  public void testAddAtPosition() {
    Solution.DLList list = new Solution.DLList();
    list.addAtPosition(new Solution.Node(102,null,null), 0);
    assertEquals(102, list.getHead().getNext().getElement());
  }

  @Test
  public void testAddAtPositionMultiple() {
    Solution.DLList list = new Solution.DLList();
    list.addAtPosition(new Solution.Node(101, null, null), 0);
    list.addAtPosition(new Solution.Node(102, null, null), 1);
    assertEquals(101, list.getHead().getNext().getElement());
    assertEquals(102, list.getHead().getNext().getNext().getElement());
  }

    @Test
  public void testAddAtPositionOutOfBounds() {
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addAtPosition(new Solution.Node(104, null, null), 6);
    assertEquals(104, list.getTail().getPrevious().getElement());
  }

  //RemoveFromPosition()
  @Test
  public void testRemoveFromPositionEmpty() {
    Solution.DLList list = new Solution.DLList();
    Solution.Node removed = list.removeFromPosition(0);
    assertEquals(null, removed);
  }

  @Test
  public void testRemoveFromPosition() {
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addLast(new Solution.Node(104,null,null));
    Solution.Node removed = list.removeFromPosition(2);
    assertEquals(103, removed.getElement());
    assertEquals(3,list.size());
  }

  @Test
  public void testRemoveFromPositionOutOfBounds() {
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addLast(new Solution.Node(104,null,null));
    Solution.Node removed = list.removeFromPosition(10);
    assertEquals(null, removed);
  }

  @Test
  public void testRemoveFromPositionNegative() {
    Solution.DLList list = new Solution.DLList();
    list.addLast(new Solution.Node(101,null,null));
    list.addLast(new Solution.Node(102,null,null));
    list.addLast(new Solution.Node(103,null,null));
    list.addLast(new Solution.Node(104,null,null));
    Solution.Node removed = list.removeFromPosition(-1);
    assertEquals(null, removed);

  }

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

  @Test
  public void testReversedFour(){
    Solution.DLList input = new Solution.DLList();
    input.addLast(new Solution.Node(101,null,null));
    input.addLast(new Solution.Node(102,null,null));
    input.addLast(new Solution.Node(103,null,null));
    input.addLast(new Solution.Node(104,null,null));
    Solution.DLList output = input.reverse();
    assertEquals(4, output.size());
    assertEquals(104, output.getHead().getNext().getElement());
  }
}