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());
}