public void TestMouseDown()
        {
            MouseEventArgs emptyMouseEvent = new MouseEventArgs(MouseButtons.Left, 0, 0, 0, 0);

            glControl.Raise(x => x.MouseDown += null, glControl, emptyMouseEvent);

            stateControl.AssertWasCalled(x => x.UpdateState(new Vector2(0, 0)));
            glControl.AssertWasCalled(x => x.Invalidate());
        }