MQTTnet/Source/MQTTnet.Tests/Server/Retain_Handling_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.Threading.Tasks;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using MQTTnet.Formatter;
using MQTTnet.Protocol;

namespace MQTTnet.Tests.Server;

// ReSharper disable InconsistentNaming
[TestClass]
public sealed class Retain_Handling_Tests : BaseTestClass
{
    [TestMethod]
    public Task Send_At_Subscribe()
    {
        return ExecuteTest(MqttRetainHandling.SendAtSubscribe, 1, 2, 3);
    }

    [TestMethod]
    public Task Do_Not_Send_On_Subscribe()
    {
        return ExecuteTest(MqttRetainHandling.DoNotSendOnSubscribe, 0, 1, 1);
    }

    [TestMethod]
    public Task Send_At_Subscribe_If_New_Subscription_Only()
    {
        return ExecuteTest(MqttRetainHandling.SendAtSubscribeIfNewSubscriptionOnly, 1, 2, 2);
    }

    async Task ExecuteTest(
        MqttRetainHandling retainHandling,
        int expectedCountAfterSubscribe,
        int expectedCountAfterSecondPublish,
        int expectedCountAfterSecondSubscribe)
    {
        using var testEnvironment = CreateTestEnvironment(MqttProtocolVersion.V500);
        await testEnvironment.StartServer();

        var client1 = await testEnvironment.ConnectClient();
        await client1.PublishStringAsync("Topic", "Payload", retain: true);

        await LongTestDelay();

        var client2 = await testEnvironment.ConnectClient();
        var applicationMessageHandler = testEnvironment.CreateApplicationMessageHandler(client2);

        var topicFilter = testEnvironment.ClientFactory.CreateTopicFilterBuilder().WithTopic("Topic").WithRetainHandling(retainHandling).Build();
        await client2.SubscribeAsync(topicFilter);
        await LongTestDelay();

        applicationMessageHandler.AssertReceivedCountEquals(expectedCountAfterSubscribe);

        await client1.PublishStringAsync("Topic", "Payload", retain: true);
        await LongTestDelay();

        applicationMessageHandler.AssertReceivedCountEquals(expectedCountAfterSecondPublish);

        await client2.SubscribeAsync(topicFilter);
        await LongTestDelay();

        applicationMessageHandler.AssertReceivedCountEquals(expectedCountAfterSecondSubscribe);
    }
}