public void VerticalAlignTest()
        {
            var renderer = Substitute.For <NullRenderer>();  // mock the renderer
            var hardware = new NullHardware(1024, 768);
            var stage    = new GuiStage();

            var box = new HBox();

            stage.AddChild(box);   // makes a size of 60x40 just through padding

            var spacerNone = new Spacer(100, 100).SetVAlign(VerticalAlign.None);

            box.AddChild(spacerNone);
            var spacerTop = new Spacer(100, 100).SetVAlign(VerticalAlign.Top);

            box.AddChild(spacerTop);
            var spacerMiddle = new Spacer(100, 100).SetVAlign(VerticalAlign.Middle);

            box.AddChild(spacerMiddle);
            var spacerBottom = new Spacer(100, 100).SetVAlign(VerticalAlign.Bottom);

            box.AddChild(spacerBottom);

            // we add one child that will free up some height
            box.AddChild(new Spacer(100, 400));

            stage.CalculateLayout(hardware);

            // since we have not set a height on the hBox yet we expect all children to be not vertically aligned
            Assert.That(box.GetLayout().GetCalculatedHeight(), Is.EqualTo(400));
            Assert.That(box.GetLayout().GetCalculatedContentHeight(), Is.EqualTo(400));

            Assert.That(spacerNone.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(0));      // NONE stays on top
            Assert.That(spacerTop.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(0));       // TOP stays on top
            Assert.That(spacerMiddle.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(150));  // MIDDLE 400 / 2 - 100 / 2
            Assert.That(spacerBottom.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(300));  // BOTTOM 400 - 100

            // new we set a height and then we expect the children to be aligned
            box.SetHeight(800);
            stage.CalculateLayout(hardware);

            Assert.That(box.GetLayout().GetCalculatedHeight(), Is.EqualTo(800));
            Assert.That(box.GetLayout().GetCalculatedContentHeight(), Is.EqualTo(400));

            Assert.That(spacerNone.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(0));      // NONE stays on top
            Assert.That(spacerTop.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(0));       // TOP stays on top
            Assert.That(spacerMiddle.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(350));  // MIDDLE 800 / 2 - 100 / 2
            Assert.That(spacerBottom.GetLayoutProcessingData().AbsoluteGeometry.Top, Is.EqualTo(700));  // BOTTOM (800 - 100)
        }