The earlier you find out about problems in your code, the less impact they have and the less it costs to remediate them. Therefore, it's helpful to move testing activities earlier in the software development lifecycle—shifting it left in the process timeline. This article explores the shift-left methodology and how you can approach shifting left in your organization.

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.