public void Append_AppendingWithCustomFields_CallsShipperWithCorrectValues() { _target.AddCustomField(new LogzioAppenderCustomField { Key = "DatKey", Value = "DatVal" }); _target.DoAppend(GetLoggingEventWithSomeData()); _target.Close(); _shipper.Received().Ship(Arg.Is <LogzioLoggingEvent>(x => (string)x.LogData["DatKey"] == "DatVal"), Arg.Any <ShipperOptions>()); }