Avalonia/tests/Perspex.Controls.UnitTests/ContentPresenterTests.cs

// -----------------------------------------------------------------------
// <copyright file="ContentPresenterTests.cs" company="Steven Kirk">
// Copyright 2014 MIT Licence. See licence.md for more information.
// </copyright>
// -----------------------------------------------------------------------

namespace Perspex.Controls.UnitTests
{
    using System.Collections.Specialized;
    using System.Linq;
    using Perspex.Controls;
    using Perspex.Controls.Presenters;
    using Xunit;

    public class ContentPresenterTests
    {
        [Fact]
        public void Setting_Content_Should_Make_Control_Appear_In_LogicalChildren()
        {
            var target = new ContentPresenter();
            var child = new Control();

            target.Content = child;
            target.ApplyTemplate();

            Assert.Equal(new[] { child }, ((ILogical)target).LogicalChildren.ToList());
        }

        [Fact]
        public void Clearing_Content_Should_Remove_From_LogicalChildren()
        {
            var target = new ContentPresenter();
            var child = new Control();

            target.Content = child;
            target.Content = null;

            Assert.Equal(new ILogical[0], ((ILogical)target).LogicalChildren.ToList());
        }

        [Fact]
        public void Changing_Content_Should_Fire_LogicalChildren_CollectionChanged()
        {
            var target = new ContentPresenter();
            var child = new Control();
            var called = false;

            ((ILogical)target).LogicalChildren.CollectionChanged += (s, e) =>
                called = e.Action == NotifyCollectionChangedAction.Add;

            target.Content = child;
            target.ApplyTemplate();

            Assert.True(called);
        }

        [Fact]
        public void Clearing_Content_Should_Fire_LogicalChildren_CollectionChanged()
        {
            var target = new ContentPresenter();
            var child = new Control();
            var called = false;

            target.Content = child;
            target.ApplyTemplate();

            ((ILogical)target).LogicalChildren.CollectionChanged += (s, e) => called = true;

            target.Content = null;
            target.ApplyTemplate();

            Assert.True(called);
        }
    }
}