Suppose we’re looking at a system rewrite where the stakeholders have none of the original engineering documentation. (This isn't surprising; documentation becomes obsolete—or even misleading—as the system changes, and corresponding docs don't get updated.) What can we do? Here are some tactics to use—and risks to anticipate—when testing a system rewrite.

The waterfall method of developing software is a bunch of translation activities: The design is a translation of the requirements into the language of architecture, the code is another, and a formal test process is a third. And with each translation, there’s the opportunity to introduce error. When your DevOps team is isolated, it creates another handoff, and another point of failure.