Fix #437: too little flips sent

Services/Donut/DonutFlipSubscriptionService.Tests.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Coflnet.Payments.Client.Api;
+using Coflnet.Sky.Commands;
+using Coflnet.Sky.Core;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using NUnit.Framework;
+
+namespace Coflnet.Sky.ModCommands.Services.Donut;
+
+public class DonutFlipSubscriptionServiceTests
+{
+    [Test]
+    public async Task ClosingOldConnectionKeepsReplacementSubscription()
+    {
+        var userApi = new Mock<IUserApi>();
+        userApi.Setup(u => u.UserUserIdOwnsProductSlugUntilGetAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<int>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync(DateTime.UtcNow.AddDays(1));
+        var service = new DonutFlipSubscriptionService(userApi.Object, new ConfigurationBuilder().Build(), NullLogger<DonutFlipSubscriptionService>.Instance);
+        var oldConnection = CreateConnection();
+        var replacement = CreateConnection();
+
+        await service.RefreshSubscriptionAsync(oldConnection.Object);
+        await service.RefreshSubscriptionAsync(replacement.Object);
+        // the old socket closes after the replacement with the same id registered
+        service.RemoveConnection(oldConnection.Object);
+        await service.DeliverAsync(new LowPricedAuction
+        {
+            Auction = new SaveAuction(),
+            AdditionalProps = new Dictionary<string, string> { { "server", DonutServerContext.Name } }
+        });
+
+        replacement.Verify(c => c.SendFlip(It.IsAny<LowPricedAuction>()), Times.Once);
+    }
+
+    private static Mock<IFlipConnection> CreateConnection()
+    {
+        var connection = new Mock<IFlipConnection>();
+        connection.SetupGet(c => c.Id).Returns(42);
+        connection.SetupGet(c => c.UserId).Returns("1");
+        connection.SetupGet(c => c.GameServer).Returns(DonutServerContext.Name);
+        connection.Setup(c => c.SendFlip(It.IsAny<LowPricedAuction>())).ReturnsAsync(true);
+        return connection;
+    }
+}

Services/Donut/DonutFlipSubscriptionService.cs

@@ -61,7 +61,8 @@ public async Task RefreshSubscriptionAsync(IFlipConnection connection)
 
     public void RemoveConnection(IFlipConnection connection)
     {
-        subscribers.TryRemove(connection.Id, out _);
+        // A replacement connection reuses the same id, only remove the subscription this connection owns
+        subscribers.TryRemove(new(connection.Id, connection));
     }
 
     public async Task DeliverAsync(LowPricedAuction flip)
@@ -74,12 +75,12 @@ public async Task DeliverAsync(LowPricedAuction flip)
             try
             {
                 if (!await entry.Value.SendFlip(flip).ConfigureAwait(false))
-                    subscribers.TryRemove(entry.Key, out _);
+                    subscribers.TryRemove(entry);
             }
             catch (Exception e)
             {
                 logger.LogError(e, "Failed to send Donut flip to connection {ConnectionId}", entry.Key);
-                subscribers.TryRemove(entry.Key, out _);
+                subscribers.TryRemove(entry);
             }
         }
     }