GroupViewUnitTests.cs

using System;
using System.Collections;
using System.Linq;
using NUnit.Framework;


namespace Xamarin.Forms.Core.UnitTests
{
	internal class NaiveLayout : Layout<View>
	{
		protected override void LayoutChildren (double x, double y, double width, double height)
		{
			foreach (var child in ((IElementController)this).LogicalChildren.Cast<View>()) {
				var result = new Rectangle (x, y, 0, 0);
				var request = child.GetSizeRequest (double.PositiveInfinity, double.PositiveInfinity);
				result.Width = request.Request.Width;
				result.Height = request.Request.Height;

				child.Layout (result);
			}
		}
	}

	[TestFixture]
	public class LayoutUnitTests : BaseTestFixture
	{
		[Test]
		public void TestRaiseChild ()
		{
			var view = new NaiveLayout ();

			var child1 = new View ();
			var child2 = new View ();
			var child3 = new View ();

			view.Children.Add (child1);
			view.Children.Add (child2);
			view.Children.Add (child3);

			bool reordered = false;
			view.ChildrenReordered += (sender, args) => reordered = true;

			view.RaiseChild (child1);

			Assert.AreEqual (child1, ((IElementController)view).LogicalChildren [2]);
			Assert.True (reordered);

			view.RaiseChild (child2);
			Assert.AreEqual (child2, ((IElementController)view).LogicalChildren [2]);
		}

		[Test]
		public void TestRaiseUnownedChild ()
		{
			var view = new NaiveLayout ();

			var child1 = new View ();
			var child2 = new View ();
			var child3 = new View ();

			view.Children.Add (child1);
			view.Children.Add (child3);

			bool reordered = false;
			view.ChildrenReordered += (sender, args) => reordered = true;

			view.RaiseChild (child2);

			Assert.False (reordered);
		}

		[Test]
		public void TestLowerChild ()
		{
			var view = new NaiveLayout ();

			var child1 = new View ();
			var child2 = new View ();
			var child3 = new View ();

			view.Children.Add (child1);
			view.Children.Add (child2);
			view.Children.Add (child3);

			bool reordered = false;
			view.ChildrenReordered += (sender, args) => reordered = true;

			view.LowerChild (child3);

			Assert.AreEqual (child3, ((IElementController)view).LogicalChildren [0]);
			Assert.True (reordered);

			view.LowerChild (child2);
			Assert.AreEqual (child2, ((IElementController)view).LogicalChildren [0]);
		}

		[Test]
		public void TestLowerUnownedChild ()
		{
			var view = new NaiveLayout ();

			var child1 = new View ();
			var child2 = new View ();
			var child3 = new View ();

			view.Children.Add (child1);
			view.Children.Add (child3);

			bool reordered = false;
			view.ChildrenReordered += (sender, args) => reordered = true;

			view.LowerChild (child2);

			Assert.False (reordered);
		}

		[Test]
		public void TestAdd ()
		{
			var view = new NaiveLayout ();
			var child1 = new View ();

			bool added = false;
			view.ChildAdded += (sender, args) => added = true;

			view.Children.Add (child1);

			Assert.True (added);
			Assert.AreEqual (child1, ((IElementController)view).LogicalChildren [0]);
		}

		[Test]
		public void TestDoubleAdd ()
		{
			var view = new NaiveLayout ();
			var child1 = new View ();
			view.Children.Add (child1);

			bool added = false;
			view.ChildAdded += (sender, args) => added = true;

			view.Children.Add (child1);

			Assert.False (added);
			Assert.AreEqual (child1, ((IElementController)view).LogicalChildren [0]);
		}

		[Test]
		public void TestRemove ()
		{
			var view = new NaiveLayout ();
			var child1 = new View ();

			view.Children.Add (child1);

			bool removed = false;
			view.ChildRemoved += (sender, args) => removed = true;

			view.Children.Remove (child1);

			Assert.True (removed);
			Assert.False (((IElementController)view).LogicalChildren.Any ());
		}

		[Test]
		public void TestGenericEnumerator ()
		{
			var view = new NaiveLayout ();

			var children = new[] {
				new View (),
				new View (),
				new View ()
			};

			foreach (var child in children)
				view.Children.Add (child);

			int i = 0;
			foreach (var child in ((IElementController)view).LogicalChildren) {
				Assert.AreEqual (children[i], child);
				i++;
			}
		}

		[Test]
		public void TestEnumerator ()
		{
			var view = new NaiveLayout ();

			var children = new [] {
				new View (),
				new View (),
				new View ()
			};

			foreach (var child in children)
				view.Children.Add (child);

			int i = 0;
			var enumerator = (((IElementController)view).LogicalChildren as IEnumerable).GetEnumerator ();
			while (enumerator.MoveNext ()) {
				Assert.AreEqual (children [i], enumerator.Current as View);
				i++;
			}
		}

		[Test]
		public void TestInitializerSyntax ()
		{
			View view1, view2;
			var group = new NaiveLayout {
				Children = {
					(view1 = new View ()),
					(view2 = new View ())
				}
			};

			Assert.AreEqual (2, ((IElementController)group).LogicalChildren.Count);
			Assert.IsTrue (((IElementController)group).LogicalChildren.Contains (view1));
			Assert.IsTrue (((IElementController)group).LogicalChildren.Contains (view2));
			Assert.AreEqual (view1, ((IElementController)group).LogicalChildren[0]);
		}

		[Test]
		public void TestChildren ()
		{
			View view1, view2;
			var group = new NaiveLayout {
				Children = {
					(view1 = new View ()),
					(view2 = new View ())
				}
			};

			Assert.AreEqual (2, group.Children.Count);
			Assert.IsTrue (group.Children.Contains (view1));
			Assert.IsTrue (group.Children.Contains (view2));
			Assert.AreEqual (view1, group.Children[0]);
		}

		[Test]
		public void TestDefaultLayout ()
		{
			View view;
			var group = new NaiveLayout {
				IsPlatformEnabled = true,
				Children = {
					(view = new View {
						WidthRequest = 50,
						HeightRequest = 20,
						IsPlatformEnabled = true,
					})
				}
			};

			group.Layout (new Rectangle (0, 0, 400, 400));

			Assert.AreEqual (new Rectangle (0, 0, 50, 20), view.Bounds);
		}

		[Test]
		public void ThrowsInvalidOperationOnSelfAdd ()
		{
			var group = new NaiveLayout ();
			Assert.Throws<InvalidOperationException> (() => group.Children.Add (group));
		}

		[Test]
		public void ReorderChildrenDoesNotRaiseChildAddedOrRemoved ()
		{
			var child1 = new BoxView ();
			var child2 = new BoxView ();
			var layout = new NaiveLayout {
				Children = {child1, child2}
			};

			var added = false;
			var removed = false;

			layout.ChildAdded += (sender, args) => added = true;
			layout.ChildRemoved += (sender, args) => removed = true;

			layout.RaiseChild (child1);

			Assert.False (added);
			Assert.False (removed);
		}

		[Test]
		public void AddToSecondLayoutRemovesFromOriginal()
		{
			var child = new BoxView();
			var layout1 = new NaiveLayout();
			var layout2 = new NaiveLayout();

			layout1.Children.Add(child);
			layout2.Children.Add(child);

			Assert.False(layout1.Children.Contains(child));
		}
	}
}