reactive/Ix.NET/Source/Tests/AsyncTests.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information. 

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Xunit;
using FluentAssertions;


namespace Tests
{
    public partial class AsyncTests
    {
#pragma warning disable xUnit1013 // Public method should be marked as test        
        public void AssertThrows<E>(Action a)
            where E : Exception
        {
            Assert.Throws<E>(a);
        }

        [Obsolete("Don't use this, use Assert.ThrowsAsync and await it", true)]
        public Task AssertThrows<E>(Func<Task> func)
            where E : Exception
        {
            return Assert.ThrowsAsync<E>(func);
        }

        public void AssertThrows<E>(Action a, Func<E, bool> assert)
            where E : Exception
        {

            var hasFailed = false;

            try
            {
                a();
            }
            catch (E e)
            {
                Assert.True(assert(e));
                hasFailed = true;
            }

            if (!hasFailed)
            {
                Assert.True(false);
            }
        }

        public void NoNext<T>(IAsyncEnumerator<T> e)
        {
            Assert.False(e.MoveNext().Result);
        }

        public void HasNext<T>(IAsyncEnumerator<T> e, T value)
        {
            Assert.True(e.MoveNext().Result);
            Assert.Equal(value, e.Current);
        }

        public async Task SequenceIdentity<T>(IAsyncEnumerable<T> enumerable)
        {
            var en1 = enumerable.GetAsyncEnumerator();
            var en2 = enumerable.GetAsyncEnumerator();

            Assert.Equal(en1.GetType(), en2.GetType());

            en1.Dispose();
            en2.Dispose();

            var e1t = enumerable.ToList();
            var e2t = enumerable.ToList();

            await Task.WhenAll(e1t, e2t);


            var e1Result = e1t.Result;
            var e2Result = e2t.Result;

            e1Result.ShouldAllBeEquivalentTo(e2Result);
        }
#pragma warning restore xUnit1013 // Public method should be marked as test        

        /// <summary>
        /// Waits WaitTimeoutMs or until cancellation is requested. If cancellation was not requested, MoveNext returns true.
        /// </summary>
        internal sealed class CancellationTestAsyncEnumerable : IAsyncEnumerable<int>
        {
            private readonly int iterationsBeforeDelay;

            public CancellationTestAsyncEnumerable(int iterationsBeforeDelay = 0)
            {
                this.iterationsBeforeDelay = iterationsBeforeDelay;
            }
            IAsyncEnumerator<int> IAsyncEnumerable<int>.GetAsyncEnumerator() => GetEnumerator();

            public TestEnumerator GetEnumerator() => new TestEnumerator(iterationsBeforeDelay);


            internal sealed class TestEnumerator : IAsyncEnumerator<int>
            {
                private readonly int iterationsBeforeDelay;

                public TestEnumerator(int iterationsBeforeDelay)
                {
                    this.iterationsBeforeDelay = iterationsBeforeDelay;
                }
                int i = -1;
                public void Dispose()
                {
                }

                public bool MoveNextWasCalled { get; private set; }

                public int Current => i;

                public async Task<bool> MoveNextAsync()
                {
                    MoveNextWasCalled = true;

                    i++;
                    if (Current >= iterationsBeforeDelay)
                    {
                        await Task.Delay(WaitTimeoutMs);
                    }

                    return true;
                }
            }
        }
    }
}