maui-linux/Xamarin.Forms.Core.UnitTests/RelativeLayoutTests.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using NUnit.Framework;

namespace Xamarin.Forms.Core.UnitTests
{
	[TestFixture]
	public class RelativeLayoutTests : BaseTestFixture
	{
		class UnitExpressionSearch : ExpressionVisitor, IExpressionSearch
		{
			List<object> results;
			Type targeType;
			public List<T> FindObjects<T>(Expression expression) where T : class
			{
				results = new List<object> ();
				targeType = typeof (T);
				Visit (expression);
				return results.Select (o => o as T).ToList ();
			}

			protected override Expression VisitMember(MemberExpression node)
			{
				if (node.Expression is ConstantExpression && node.Member is FieldInfo) {
					var container = ((ConstantExpression)node.Expression).Value;
					var value = ((FieldInfo)node.Member).GetValue (container);

					if (targeType.IsInstanceOfType (value)) {
						results.Add (value);
					}
				}
				return base.VisitMember (node);
			}
		}

		[SetUp]
		public override void Setup()
		{
			base.Setup ();
			ExpressionSearch.Default = new UnitExpressionSearch ();
		}

		[TearDown]
		public override void TearDown()
		{
			base.TearDown ();
			ExpressionSearch.Default = new UnitExpressionSearch ();
		}

		[Test]
		public void SimpleLayout ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child,
			                    Constraint.Constant (30),
			                    Constraint.Constant (20),
			                    Constraint.RelativeToParent (parent => parent.Height / 2),
			                    Constraint.RelativeToParent (parent => parent.Height / 4));

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 50, 25), child.Bounds);
		}

		[Test]
		public void SimpleExpressionLayout ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child = new View {
				IsPlatformEnabled = true
			};
			
			relativeLayout.Children.Add (child,
								() => 30,
								() => 20,
								() => relativeLayout.Height / 2,
								() => relativeLayout.Height / 4);

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 50, 25), child.Bounds);
		}

		[Test]
		public void SimpleBoundsSizing ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child, () => new Rectangle (30, 20, relativeLayout.Height / 2, relativeLayout.Height / 4));

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 50, 25), child.Bounds);
		}

		[Test]
		public void UnconstrainedSize()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child = new View {
				IsPlatformEnabled = true,
				WidthRequest = 25,
				HeightRequest = 50
			};

			relativeLayout.Children.Add (child, Constraint.Constant (30), Constraint.Constant (20));

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 25, 50), child.Bounds);
		}

		[Test]
		public void ViewRelativeLayout ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
								Constraint.Constant (30),
								Constraint.Constant (20),
								Constraint.RelativeToParent (parent => parent.Height / 5),
								Constraint.RelativeToParent (parent => parent.Height / 10));

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child2,
			                    Constraint.RelativeToView (child1, (layout, view) => view.Bounds.Right + 10),
			                    Constraint.RelativeToView (child1, (layout, view) => view.Y),
			                    Constraint.RelativeToView (child1, (layout, view) => view.Width),
			                    Constraint.RelativeToView (child1, (layout, view) => view.Height));

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 20, 10), child1.Bounds);
			Assert.AreEqual (new Rectangle (60, 20, 20, 10), child2.Bounds);
		}

		[Test]
		public void ViewRelativeLayoutWithExpressions()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
								() => 30,
								() => 20,
								() => relativeLayout.Height / 5,
								() => relativeLayout.Height / 10);

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child2,
								() => child1.Bounds.Right + 10,
								() => child1.Y,
								() => child1.Width,
								() => child1.Height);

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 20, 10), child1.Bounds);
			Assert.AreEqual (new Rectangle (60, 20, 20, 10), child2.Bounds);
		}

		[Test]
		public void ViewRelativeToMultipleViews ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
								Constraint.Constant (30),
								Constraint.Constant (20),
								Constraint.RelativeToParent (parent => parent.Height / 5),
								Constraint.RelativeToParent (parent => parent.Height / 10));

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child2,
								Constraint.Constant (30),
								Constraint.Constant (50),
								Constraint.RelativeToParent (parent => parent.Height / 4),
								Constraint.RelativeToParent (parent => parent.Height / 5));

			var child3 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child3,
								Constraint.RelativeToView (child1, (layout, view) => view.Bounds.Right + 10),
								Constraint.RelativeToView (child2, (layout, view) => view.Y),
								Constraint.RelativeToView (child1, (layout, view) => view.Width),
								Constraint.RelativeToView (child2, (layout, view) => view.Height * 2));

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 20, 10), child1.Bounds);
			Assert.AreEqual (new Rectangle (30, 50, 25, 20), child2.Bounds);
			Assert.AreEqual (new Rectangle (60, 50, 20, 40), child3.Bounds);
		}

		[Test]
		public void ExpressionRelativeToMultipleViews()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
								Constraint.Constant (30),
								Constraint.Constant (20),
								Constraint.RelativeToParent (parent => parent.Height / 5),
								Constraint.RelativeToParent (parent => parent.Height / 10));

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child2,
								Constraint.Constant (30),
								Constraint.Constant (50),
								Constraint.RelativeToParent (parent => parent.Height / 4),
								Constraint.RelativeToParent (parent => parent.Height / 5));

			var child3 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child3,
								() => child1.Bounds.Right + 10,
								() => child1.Y,
								() => child1.Width + child2.Width,
								() => child1.Height * 2 + child2.Height);

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 20, 10), child1.Bounds);
			Assert.AreEqual (new Rectangle (30, 50, 25, 20), child2.Bounds);
			Assert.AreEqual (new Rectangle (60, 20, 45, 40), child3.Bounds);
		}

		[Test]
		public void ThreePassLayout ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
								Constraint.Constant (30),
								Constraint.Constant (20),
								Constraint.RelativeToParent (parent => parent.Height / 5),
								Constraint.RelativeToParent (parent => parent.Height / 10));

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child2,
								Constraint.Constant (30),
								Constraint.Constant (50),
								Constraint.RelativeToParent (parent => parent.Height / 4),
								Constraint.RelativeToParent (parent => parent.Height / 5));

			var child3 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child3,
								Constraint.RelativeToView (child1, (layout, view) => view.Bounds.Right + 10),
								Constraint.RelativeToView (child2, (layout, view) => view.Y),
								Constraint.RelativeToView (child1, (layout, view) => view.Width),
								Constraint.RelativeToView (child2, (layout, view) => view.Height * 2));

			var child4 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child4,
								Constraint.RelativeToView (child1, (layout, view) => view.Bounds.Right + 10),
								Constraint.RelativeToView (child2, (layout, view) => view.Y),
								Constraint.RelativeToView (child1, (layout, view) => view.Width),
								Constraint.RelativeToView (child3, (layout, view) => view.Height * 2));

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 20, 10), child1.Bounds);
			Assert.AreEqual (new Rectangle (30, 50, 25, 20), child2.Bounds);
			Assert.AreEqual (new Rectangle (60, 50, 20, 40), child3.Bounds);
			Assert.AreEqual (new Rectangle (60, 50, 20, 80), child4.Bounds);
		}

		[Test]
		public void ThreePassLayoutWithExpressions()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
			                    x: () => 30,
			                    y: () => 20,
			                    width: () => relativeLayout.Height / 5,
			                    height: () => relativeLayout.Height / 10);

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child2,
			                    x: () => 30,
			                    y: () => 50,
			                    width: () => relativeLayout.Height / 4,
			                    height: () => relativeLayout.Height / 5);

			var child3 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child3,
			                    x: () => child1.Bounds.Right + 10,
			                    y: () => child2.Y,
			                    width: () => child1.Width,
			                    height: () => child2.Height * 2);

			var child4 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child4,
			                    x: () => child1.Bounds.Right + 10,
			                    y: () => child2.Y,
			                    width: () => child1.Width,
			                    height: () => child3.Height * 2);

			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.AreEqual (new Rectangle (30, 20, 20, 10), child1.Bounds);
			Assert.AreEqual (new Rectangle (30, 50, 25, 20), child2.Bounds);
			Assert.AreEqual (new Rectangle (60, 50, 20, 40), child3.Bounds);
			Assert.AreEqual (new Rectangle (60, 50, 20, 80), child4.Bounds);
		}

		[Test]
		public void ThrowsWithUnsolvableConstraints ()
		{
			var relativeLayout = new RelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			var child2 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child1,
								() => 30,
								() => 20,
								() => child2.Height / 5,
								() => relativeLayout.Height / 10);

			relativeLayout.Children.Add (child2,
								() => child1.Bounds.Right + 10,
								() => child1.Y,
								() => child1.Width,
								() => child1.Height);

			Assert.Throws<UnsolvableConstraintsException> (() => relativeLayout.Layout (new Rectangle (0, 0, 100, 100)));
		}

		[Test]
		public void ChildAddedBeforeLayoutChildrenAfterInitialLayout ()
		{
			var relativeLayout = new MockRelativeLayout {
				Platform = new UnitPlatform (),
				IsPlatformEnabled = true
			};

			var child = new View {
				IsPlatformEnabled = true
			};

			var child1 = new View {
				IsPlatformEnabled = true
			};

			relativeLayout.Children.Add (child,
				Constraint.Constant (30),
				Constraint.Constant (20),
				Constraint.RelativeToParent (parent => parent.Height / 2),
				Constraint.RelativeToParent (parent => parent.Height / 4));

		
			relativeLayout.Layout (new Rectangle (0, 0, 100, 100));

			Assert.IsTrue (relativeLayout.childAdded);
			Assert.IsTrue (relativeLayout.added);
			Assert.IsTrue (relativeLayout.layoutChildren);

			relativeLayout.layoutChildren = relativeLayout.added = relativeLayout.childAdded = false;

			Assert.IsFalse (relativeLayout.childAdded);
			Assert.IsFalse (relativeLayout.added);
			Assert.IsFalse (relativeLayout.layoutChildren);

			relativeLayout.Children.Add (child1,
				Constraint.Constant (30),
				Constraint.Constant (20),
				Constraint.RelativeToParent (parent => parent.Height / 2),
				Constraint.RelativeToParent (parent => parent.Height / 4));

			Assert.IsTrue (relativeLayout.childAdded);
			Assert.IsTrue (relativeLayout.added);
			Assert.IsTrue (relativeLayout.layoutChildren);

		}
	}

	internal class MockRelativeLayout : RelativeLayout
	{
		internal bool layoutChildren;
		internal bool childAdded;
		internal bool added;

		protected override void LayoutChildren (double x, double y, double width, double height)
		{
			if(added)
				layoutChildren = true;

			base.LayoutChildren (x, y, width, height);
		}

		protected override void OnAdded (View view)
		{
			if(childAdded)
				added = true;
			base.OnAdded (view);
		}

		protected override void OnChildAdded (Element child)
		{
			childAdded = true;
			base.OnChildAdded (child);
		}
	}
}