public void RemoveAllShapes()
{
var c = new CompositeShape();
var rpoint1 = new Point(20, 20);
var rpoint2 = new Point(30, 20);
var rpoint3 = new Point(30, 30);
var rpoint4 = new Point(20, 30);
var rect = new Rectangle(rpoint1, rpoint2, rpoint3, rpoint4);
c.Add(rect);
var tpoint1 = new Point(0, 0);
var tpoint2 = new Point(3, 0);
var tpoint3 = new Point(0, 3);
var triangle = new Triangle(tpoint1, tpoint2, tpoint3);
c.Add(triangle);
c.RemoveAllShapes();
Assert.AreEqual(0, c.Points.Count);
Assert.AreEqual(0, c.thisShapesList.Count);
}