diff --git a/src/contrib/cluster/Akka.Cluster.Sharding.Tests/ShardingBufferAdapterSpec.cs b/src/contrib/cluster/Akka.Cluster.Sharding.Tests/ShardingBufferAdapterSpec.cs
index e935c369f4f..55f3dbeaf68 100644
--- a/src/contrib/cluster/Akka.Cluster.Sharding.Tests/ShardingBufferAdapterSpec.cs
+++ b/src/contrib/cluster/Akka.Cluster.Sharding.Tests/ShardingBufferAdapterSpec.cs
@@ -7,6 +7,7 @@
 
 using System;
 using System.Collections.Immutable;
+using System.Threading.Tasks;
 using Akka.Actor;
 using Akka.Cluster.Tools.Singleton;
 using Akka.Configuration;
@@ -72,18 +73,20 @@ public object Apply(object message, IActorContext context)
     private const string ShardTypeName = "Caat";
 
     private static Config SpecConfig =>
-        ConfigurationFactory.ParseString(@"
-            akka.loglevel = DEBUG
-            akka.actor.provider = cluster
-            akka.remote.dot-netty.tcp.port = 0
-            akka.remote.log-remote-lifecycle-events = off
-
-            akka.test.single-expect-default = 5 s
-            akka.cluster.sharding.state-store-mode = ""ddata""
-            akka.cluster.sharding.verbose-debug-logging = on
-            akka.cluster.sharding.fail-on-invalid-entity-state-transition = on
-            akka.cluster.sharding.distributed-data.durable.keys = []")
-            .WithFallback(ClusterSingletonManager.DefaultConfig()
+        ConfigurationFactory.ParseString("""
+                                         
+                                                     akka.loglevel = DEBUG
+                                                     akka.actor.provider = cluster
+                                                     akka.remote.dot-netty.tcp.port = 0
+                                                     akka.remote.log-remote-lifecycle-events = off
+                                         
+                                                     akka.test.single-expect-default = 5 s
+                                                     akka.cluster.sharding.state-store-mode = "ddata"
+                                                     akka.cluster.sharding.verbose-debug-logging = on
+                                                     akka.cluster.sharding.fail-on-invalid-entity-state-transition = on
+                                                     akka.cluster.sharding.distributed-data.durable.keys = []
+                                         """)
+            .WithFallback(ClusterSingleton.DefaultConfig()
             .WithFallback(ClusterSharding.DefaultConfig()));
 
     private readonly AtomicCounter _counterA = new (0);
@@ -105,9 +108,11 @@ public ShardingBufferAdapterSpec(ITestOutputHelper helper) : base(SpecConfig, he
         
         InitializeLogger(_sysB, "[sysB]");
         
+        // ReSharper disable VirtualMemberCallInConstructor
         _pA = CreateTestProbe(_sysA);
         _pB = CreateTestProbe(_sysB);
-
+        // ReSharper restore VirtualMemberCallInConstructor
+        
         ClusterSharding.Get(_sysA).SetShardingBufferMessageAdapter(new TestMessageAdapter(_counterA));
         ClusterSharding.Get(_sysB).SetShardingBufferMessageAdapter(new TestMessageAdapter(_counterB));
         
@@ -134,37 +139,38 @@ private IActorRef StartShard(ActorSystem sys)
     }
     
     [Fact(DisplayName = "ClusterSharding buffer message adapter must be called when message was buffered")]
-    public void ClusterSharding_must_initialize_cluster_and_allocate_sharded_actors()
+    public async Task ClusterSharding_must_initialize_cluster_and_allocate_sharded_actors()
     {
-        Cluster.Get(_sysA).Join(Cluster.Get(_sysA).SelfAddress); // coordinator on A
+        await Cluster.Get(_sysA).JoinAsync(Cluster.Get(_sysA).SelfAddress); // coordinator on A
         
-        AwaitAssert(() =>
+        await AwaitAssertAsync(() =>
         {
             Cluster.Get(_sysA).SelfMember.Status.Should().Be(MemberStatus.Up);
         }, TimeSpan.FromSeconds(1));
 
-        Cluster.Get(_sysB).Join(Cluster.Get(_sysA).SelfAddress);
+        await Cluster.Get(_sysB).JoinAsync(Cluster.Get(_sysA).SelfAddress);
 
-        Within(TimeSpan.FromSeconds(10), () =>
+        await WithinAsync(TimeSpan.FromSeconds(10), async () =>
         {
-            AwaitAssert(() =>
+            await AwaitAssertAsync(async () =>
             {
                 foreach (var s in ImmutableHashSet.Create(_sysA, _sysB))
                 {
                     Cluster.Get(s).SendCurrentClusterState(TestActor);
-                    ExpectMsg<ClusterEvent.CurrentClusterState>().Members.Count.Should().Be(2);
+                    (await ExpectMsgAsync<ClusterEvent.CurrentClusterState>()).Members.Count.Should().Be(2);
                 }
             });
         });
 
-        _regionA.Tell(1, _pA.Ref);
-        _pA.ExpectMsg(1);
+        // need to make sure that ShardingEnvelope doesn't impacted by this change
+        _regionA.Tell(new ShardingEnvelope("1", 1), _pA.Ref);
+        await _pA.ExpectMsgAsync(1);
 
         _regionB.Tell(2, _pB.Ref);
-        _pB.ExpectMsg(2);
+        await _pB.ExpectMsgAsync(2);
 
         _regionB.Tell(3, _pB.Ref);
-        _pB.ExpectMsg(3);
+        await _pB.ExpectMsgAsync(3);
 
         var counterAValue = _counterA.Current;
         var counterBValue = _counterB.Current;
@@ -175,13 +181,13 @@ public void ClusterSharding_must_initialize_cluster_and_allocate_sharded_actors(
         counterBValue.Should().BeGreaterOrEqualTo(2);
         
         _regionA.Tell(1, _pA.Ref);
-        _pA.ExpectMsg(1);
+        await _pA.ExpectMsgAsync(1);
 
         _regionB.Tell(2, _pB.Ref);
-        _pB.ExpectMsg(2);
+        await _pB.ExpectMsgAsync(2);
 
         _regionB.Tell(3, _pB.Ref);
-        _pB.ExpectMsg(3);
+        await _pB.ExpectMsgAsync(3);
         
         // Each entity should not have their messages buffered once they were instantiated
         _counterA.Current.Should().Be(counterAValue);