tokens for updater and unit tests

CoreUnitTests/Infrastructure/UpdateDefinitionExtensions.cs

@@ -0,0 +1,21 @@
+using System;
+using MongoDB.Bson.Serialization;
+using MongoDB.Driver;
+
+namespace CoreUnitTests.Infrastructure;
+
+public static class UpdateDefinitionExtensions
+{
+    public static bool EquivalentTo<TDocument>(this UpdateDefinition<TDocument> update, UpdateDefinition<TDocument> expected)
+    {
+        var renderedUpdate = update.Render(
+            BsonSerializer.SerializerRegistry.GetSerializer<TDocument>(),
+            BsonSerializer.SerializerRegistry);
+
+        var renderedExpected = expected.Render(
+            BsonSerializer.SerializerRegistry.GetSerializer<TDocument>(),
+            BsonSerializer.SerializerRegistry);
+
+        return renderedUpdate.Equals(renderedExpected);
+    }
+}