add redis test and fix bug

Author: datwelk

src/SignalR/server/StackExchangeRedis/src/RedisHubLifetimeManager.cs

@@ -254,35 +254,31 @@ public override Task SendConnectionsAsync(IReadOnlyList<string> connectionIds, s
     }
 
     /// <inheritdoc />
-    public override Task SendGroupsAsync(IReadOnlyList<string> groupNames, string methodName, object?[] args, CancellationToken cancellationToken = default)
+    public override async Task SendGroupsAsync(IReadOnlyList<string> groupNames, string methodName, object?[] args, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(groupNames);
-        var publishTasks = new List<Task>(groupNames.Count);
-        var payload = _protocol.WriteInvocation(methodName, args);
         var connections = new HashSet<string>();
 
         foreach (var groupName in groupNames)
         {
             if (!string.IsNullOrEmpty(groupName))
             {
-                var connectionStore = _groups.GetStore(groupName);
-                if (connectionStore != null)
+                var groupChannel = _channels.Group(groupName);
+                if (groupChannel != null)
                 {
-                    foreach (var connection in connectionStore)
+                    var connectionStore = _groups.GetStore(groupChannel);
+                    if (connectionStore != null)
                     {
-                        connections.Add(connection.ConnectionId);
+                        foreach (var connection in connectionStore)
+                        {
+                            connections.Add(connection.ConnectionId);
+                        }
                     }
                 }
             }
         }
 
-        // Send to unique connections
-        foreach (var connectionId in connections)
-        {
-            publishTasks.Add(PublishAsync(_channels.Connection(connectionId), payload));
-        }
-
-        return Task.WhenAll(publishTasks);
+        await SendConnectionsAsync(connections.ToList(), methodName, args, cancellationToken);
     }
 
     /// <inheritdoc />

src/SignalR/server/StackExchangeRedis/test/RedisHubLifetimeManagerTests.cs

@@ -145,6 +145,30 @@ public async Task PatternGroupAndUser()
         }
     }
 
+    [Fact]
+    public async Task ConnectionInMultipleGroups_ReceivesMessageOnlyOnce()
+    {
+        var server = new TestRedisServer();
+
+        using (var client = new TestClient())
+        {
+            var manager = CreateLifetimeManager(server);
+            var connection = HubConnectionContextUtils.Create(client.Connection);
+
+            await manager.OnConnectedAsync(connection).DefaultTimeout();
+            await manager.AddToGroupAsync(connection.ConnectionId, "group1").DefaultTimeout();
+            await manager.AddToGroupAsync(connection.ConnectionId, "group2").DefaultTimeout();
+
+            await manager.SendGroupsAsync(new[] { "group1", "group2" }, "Hello", new object[] { "World" }).DefaultTimeout();
+
+            var message = Assert.IsType<InvocationMessage>(await client.ReadAsync().DefaultTimeout());
+            Assert.Equal("Hello", message.Target);
+            Assert.Single(message.Arguments);
+            Assert.Equal("World", (string)message.Arguments[0]);
+            Assert.Null(client.TryRead());
+        }
+    }
+
     public override TestRedisServer CreateBackplane()
     {
         return new TestRedisServer();