System, and computer program product embodiments for triggering error injection into a function under test using a serialization resource are provided. A test process invokes the function under test immediately after relinquishing exclusive control of the serialization resource. An error-injection process injects the error into the running function after gaining exclusive control of the serialization resource from the test process. The error-injection process may add a delay to inject the error. If the processes are repeated, the error-injection process may vary the delay, perhaps randomly, over a specified time window to thoroughly exercise the function's error recovery routine.