Update NodeSystemTests.cs

tests/PixiEditor.Backend.Tests/NodeSystemTests.cs

@@ -24,6 +24,11 @@ public class NodeSystemTests
 {
     private readonly ITestOutputHelper output;
 
+    private Type[] knownNonSerializableTypes = new[]
+    {
+        typeof(Filter)
+    };
+
     public NodeSystemTests(ITestOutputHelper output)
     {
         this.output = output;
@@ -142,6 +147,7 @@ public class NodeSystemTests
 
             foreach (var input in node.InputProperties)
             {
+                if (knownNonSerializableTypes.Contains(input.ValueType)) continue;
                 if (input.ValueType.IsAssignableTo(typeof(Delegate))) continue;
                 bool hasFactory = factories.Any(x => x.OriginalType == input.ValueType);
                 Assert.True(