You work with a team that is upgrading an ASP.NET Web Forms application to an ASP.NET MVC 4 application and adding enhancements. The look, feel, and navigation of the application will remain the same, but the underlying structure must be modified in anticipation of future features. The business rules that are part of the application are poorly documented and complicated. The team is starting to run behind schedule. They have stopped working on new functionality, but they are continuing the migration.