/**
   * Accuracy Test of the <code>setEndingPoint(Point)</code> and <code>getEndingPoint()</code>
   * methods.
   */
  public void testEndingPoint_Operation() {
    // get the attribute endPoint to check the get operation.
    assertEquals("The endPoint default to Point(0, 0).", new Point(0, 0), test.getEndingPoint());

    Point newPoint = new Point(2, 4);
    // set the endPoint.
    test.setEndingPoint(newPoint);
    //  get the attribute endPoint to check the set operation.
    assertEquals("The endPoint should be Point(2, 4).", newPoint, test.getEndingPoint());
  }
  /** Accuracy Test of the <code>EdgeEnding</code>'s constructor. */
  public void testConstructor() {
    // creat a new instance to check the constructor.
    assertNotNull("Constructor should work well.", new MockEdgeEnding());

    //  get the attribute endPoint to check the constructor.
    assertEquals("The endPoint default to Point(0, 0).", new Point(0, 0), test.getEndingPoint());
  }
 /** Accuracy Test of the <code>setAngle(double)</code> and <code>getAngle()</code> methods. */
 public void testAngle_Operation() {
   // set the angle.
   test.setAngle(1.24);
   //  get the attribute angle to check the set operation.
   assertEquals("The angle should be 1.24.", 1.24, test.getAngle());
 }