In various embodiments, a method, system, and computer program product for injecting error code include logic and/or program instructions configured for determining critical points in executing code of software under test, building a testcase to invoke the software under test, determining an appropriate response action for each critical point based on an error encountered at each critical point, injecting a critical point segment into the executing code at a corresponding critical point, and outputting a unique identifier of each critical point segment, the testcase being configured to issue commands, with each command limiting which of one or more critical points remains active based on one of: a number of times the one or more critical points have been accessed in the executing code, a number of times a critical point has been skipped, and an amount of times a critical point has been accessed versus skipped.