diff --git a/Assets/Mirror/Tests/Editor/SyncSetTest.cs b/Assets/Mirror/Tests/Editor/SyncSetTest.cs
index 6cc754a2b..bb106c0ce 100644
--- a/Assets/Mirror/Tests/Editor/SyncSetTest.cs
+++ b/Assets/Mirror/Tests/Editor/SyncSetTest.cs
@@ -56,6 +56,16 @@ public void TestInit()
             Assert.That(clientSyncSet, Is.EquivalentTo(new[] { "Hello", "World", "!" }));
         }
 
+        // test the '= List<int>{1,2,3}' constructor.
+        // it calls .Add(1); .Add(2); .Add(3) in the constructor.
+        // (the OnDirty change broke this and we didn't have a test before)
+        [Test]
+        public void CurlyBracesConstructor()
+        {
+            SyncHashSet<int> set = new SyncHashSet<int>{1,2,3};
+            Assert.That(set.Count, Is.EqualTo(3));
+        }
+
         [Test]
         public void TestAdd()
         {