MongoDB.DriverUnitTests.MongoDBRefTests.TestNull C# (CSharp) Метод

        public void TestNull()
        {
            var id = ObjectId.GenerateNewId();
            var obj = new C { Id = id, DBRef = null };
            var json = obj.ToJson();
            var expected = "{ '_id' : ObjectId('#id'), 'DBRef' : null }";
            expected = expected.Replace("#id", id.ToString());
            expected = expected.Replace("'", "\"");
            Assert.AreEqual(expected, json);

            var bson = obj.ToBson();
            var rehydrated = BsonSerializer.Deserialize<C>(bson);
            Assert.IsTrue(bson.SequenceEqual(rehydrated.ToBson()));
        }