MQTTnet/Source/MQTTnet.Tests/Internal/BlockingQueue_Tests.cs

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

using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using MQTTnet.Internal;

namespace MQTTnet.Tests.Internal;

// ReSharper disable InconsistentNaming
[TestClass]
public class BlockingQueue_Tests
{
    [TestMethod]
    public void Preserve_Order()
    {
        var queue = new BlockingQueue<string>();
        queue.Enqueue("a");
        queue.Enqueue("b");
        queue.Enqueue("c");

        Assert.AreEqual(3, queue.Count);

        Assert.AreEqual("a", queue.Dequeue());
        Assert.AreEqual("b", queue.Dequeue());
        Assert.AreEqual("c", queue.Dequeue());
    }

    [TestMethod]
    public void Remove_First_Items()
    {
        var queue = new BlockingQueue<string>();
        queue.Enqueue("a");
        queue.Enqueue("b");
        queue.Enqueue("c");

        Assert.AreEqual("a", queue.RemoveFirst());
        Assert.AreEqual("b", queue.RemoveFirst());

        Assert.AreEqual(1, queue.Count);

        Assert.AreEqual("c", queue.Dequeue());
    }

    [TestMethod]
    public void Clear_Items()
    {
        var queue = new BlockingQueue<string>();
        queue.Enqueue("a");
        queue.Enqueue("b");
        queue.Enqueue("c");

        Assert.AreEqual(3, queue.Count);

        queue.Clear();

        Assert.AreEqual(0, queue.Count);
    }

    [TestMethod]
    public async Task Wait_For_Item()
    {
        var queue = new BlockingQueue<string>();

        string item = null;
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
        Task.Run(() =>
        {
            item = queue.Dequeue();
        });
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed

        await Task.Delay(100);

        Assert.AreEqual(0, queue.Count);
        Assert.IsNull(item);

        queue.Enqueue("x");

        await Task.Delay(100);

        Assert.AreEqual("x", item);
        Assert.AreEqual(0, queue.Count);
    }

    [TestMethod]
    public void Wait_For_Items()
    {
        var number = 0;

        var queue = new BlockingQueue<int>();

#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
        Task.Run(async () =>
        {
            while (true)
            {
                queue.Enqueue(1);
                await Task.Delay(100);
            }
        });
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed

        while (number < 50)
        {
            queue.Dequeue();
            Interlocked.Increment(ref number);
        }
    }

    [TestMethod]
    public void Use_Disposed_Queue()
    {
        Assert.ThrowsExactly<OperationCanceledException>(() =>
        {

            var queue = new BlockingQueue<int>();
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
            Task.Run(() =>
            {
                Thread.Sleep(1000);
                queue.Dispose();
            });
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed

            queue.Dequeue(new CancellationTokenSource(TimeSpan.FromSeconds(2)).Token);
        });
    }
}