diff --git a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerParticipantsList.cs b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerParticipantsList.cs
index a3e6c8de3b..a44ce87738 100644
--- a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerParticipantsList.cs
+++ b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerParticipantsList.cs
@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Testing;
@@ -48,7 +49,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.User).Distinct().Count() == 1);
 
-            AddStep("add non-resolvable user", () => Client.AddNullUser(-3));
+            AddStep("add non-resolvable user", () => Client.AddNullUser());
+            AddAssert("null user added", () => Client.Room.AsNonNull().Users.Count(u => u.User == null) == 1);
 
             AddUntilStep("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.User).Distinct().Count() == 2);
         }
diff --git a/osu.Game/Tests/Visual/Multiplayer/TestMultiplayerClient.cs b/osu.Game/Tests/Visual/Multiplayer/TestMultiplayerClient.cs
index 67b79d7390..f2da66d666 100644
--- a/osu.Game/Tests/Visual/Multiplayer/TestMultiplayerClient.cs
+++ b/osu.Game/Tests/Visual/Multiplayer/TestMultiplayerClient.cs
@@ -61,7 +61,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             return roomUser;
         }
 
-        public void AddNullUser(int userId) => ((IMultiplayerClient)this).UserJoined(new MultiplayerRoomUser(userId));
+        public void AddNullUser() => ((IMultiplayerClient)this).UserJoined(new MultiplayerRoomUser(TestUserLookupCache.NULL_USER_ID));
 
         public void RemoveUser(User user)
         {
diff --git a/osu.Game/Tests/Visual/TestUserLookupCache.cs b/osu.Game/Tests/Visual/TestUserLookupCache.cs
index d2941b5bd5..b73e81d0dd 100644
--- a/osu.Game/Tests/Visual/TestUserLookupCache.cs
+++ b/osu.Game/Tests/Visual/TestUserLookupCache.cs
@@ -10,10 +10,22 @@ namespace osu.Game.Tests.Visual
 {
     public class TestUserLookupCache : UserLookupCache
     {
-        protected override Task<User> ComputeValueAsync(int lookup, CancellationToken token = default) => Task.FromResult(new User
+        /// <summary>
+        /// A special user ID which <see cref="ComputeValueAsync"/> would return a <see langword="null"/> <see cref="User"/> for.
+        /// As a simulation to what a regular <see cref="UserLookupCache"/> would return in the case of failing to fetch the user.
+        /// </summary>
+        public const int NULL_USER_ID = -1;
+
+        protected override Task<User> ComputeValueAsync(int lookup, CancellationToken token = default)
         {
-            Id = lookup,
-            Username = $"User {lookup}"
-        });
+            if (lookup == NULL_USER_ID)
+                return Task.FromResult((User)null);
+
+            return Task.FromResult(new User
+            {
+                Id = lookup,
+                Username = $"User {lookup}"
+            });
+        }
     }
 }