public void HorizontalLayoutTest()
{
var renderer = Substitute.For <NullRenderer>(); // mock the renderer
var hardware = new NullHardware(1024, 768);
var stage = new GuiStage();
var hBox = new HBox().SetX(10).SetY(20).SetPadding(10, 20, 30, 40); // makes a size of 60x40 just through padding
stage.AddChild(hBox);
stage.CalculateLayout(hardware);
Assert.That(hBox.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(10, 20, 60, 40)));
// add a child
var spacer1 = new Spacer(200, 100);
hBox.AddChild(spacer1); // should increase the size by 200x100
stage.CalculateLayout(hardware);
Assert.That(hBox.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(10, 20, 260, 140)));
// check the absolute position of spacer1
Assert.That(spacer1.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(50, 30, 200, 100)));
// add another child
var spacer2 = new Spacer(300, 200);
hBox.AddChild(spacer2); // should increase the size by 200x100
stage.CalculateLayout(hardware);
Assert.That(hBox.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(10, 20, 560, 240)));
// check the absolute position of spacer1
Assert.That(spacer1.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(50, 30, 200, 100)));
// check the absolute position of spacer1
Assert.That(spacer2.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(250, 30, 300, 200)));
// check setting the spacing
hBox.SetSpacing(100);
stage.CalculateLayout(hardware);
Assert.That(hBox.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(10, 20, 660, 240)));
// check the absolute position of spacer1
Assert.That(spacer1.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(50, 30, 200, 100)));
// check the absolute position of spacer1
Assert.That(spacer2.GetLayoutProcessingData().AbsoluteGeometry, Is.EqualTo(new Rectangle(350, 30, 300, 200)));
}