如何在软件开发实践的早期发现与业务相关的错误？

I'm working with good group of very sharp developers on one of my client's premises. We are coding correctly around NullPointerException and other exceptions, so we don't have those. But when it comes to business rules we have some mistakes and find issues when already in production. Granted we have very fast paced environment, and deployment to production commanded by management team, not development one. But we passed "green light" with QA and Data Quality teams.I'm working with good group of very sharp devel