using System;
using System.Linq;
using FluentAssertions;
using NUnit.Framework;

namespace Chernobyl.Destruction
{
    [TestFixture, Description("Tests for Disposable types.")]
    public class DisposableTests
    {
        [Test, Description("Ensures Disposable.DepthFirst(IDisposable) returns expected items.")]
        public void Decompose()
        {
            var disposable = Disposable.Join
            (
                Disposable.Join
                (
                    new Val(1),
                    new Val(2),
                    Disposable.Join<IDisposable>(new Val(3))
                ),
                Disposable.Join<IDisposable>(new Val(4))
            );

            var vals = disposable.Decompose().OfType<Val>().Select(v => v.X).ToArray();
            vals.Should().BeEquivalentTo(1, 2, 3, 4).And.BeInAscendingOrder();
        }

        class Val : IDisposable
        {
            public Val(int x) { X = x; }
            public void Dispose() { }
            public int X { get; }
        }
    }
}