public void HorizontalAlignTest()
{
var renderer = Substitute.For <NullRenderer>(); // mock the renderer
var hardware = new NullHardware(1024, 768);
var stage = new GuiStage();
var box = new VBox();
stage.AddChild(box); // makes a size of 60x40 just through padding
var spacerNone = new Spacer(100, 100).SetHAlign(HorizontalAlign.None);
box.AddChild(spacerNone);
var spacerLeft = new Spacer(100, 100).SetHAlign(HorizontalAlign.Left);
box.AddChild(spacerLeft);
var spacerCenter = new Spacer(100, 100).SetHAlign(HorizontalAlign.Center);
box.AddChild(spacerCenter);
var spacerRight = new Spacer(100, 100).SetHAlign(HorizontalAlign.Right);
box.AddChild(spacerRight);
// we add one child that will free up some width
box.AddChild(new Spacer(400, 100));
stage.CalculateLayout(hardware); // layout
// since we have not set a height on the hBox yet we expect all children to be not vertically aligned
Assert.That(box.GetLayout().GetCalculatedWidth(), Is.EqualTo(400));
Assert.That(box.GetLayout().GetCalculatedContentWidth(), Is.EqualTo(400));
Assert.That(spacerNone.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(0)); // NONE stays on top
Assert.That(spacerLeft.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(0)); // TOP stays on top
Assert.That(spacerCenter.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(150)); // MIDDLE 400 / 2 - 100 / 2
Assert.That(spacerRight.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(300)); // BOTTOM 400 - 100
// new we set a height and then we expect the children to be aligned
box.SetWidth(800);
stage.CalculateLayout(hardware); // layout
Assert.That(box.GetLayout().GetCalculatedWidth(), Is.EqualTo(800));
Assert.That(box.GetLayout().GetCalculatedContentWidth(), Is.EqualTo(400));
Assert.That(spacerNone.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(0)); // NONE stays on top
Assert.That(spacerLeft.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(0)); // TOP stays on top
Assert.That(spacerCenter.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(350)); // MIDDLE 800 / 2 - 100 / 2
Assert.That(spacerRight.GetLayoutProcessingData().AbsoluteGeometry.Left, Is.EqualTo(700)); // BOTTOM (800 - 100)
}