Testing a data coherency algorithm of a multi-processor environment. The testing includes implementing a global time incremented every processor cycle and used for timestamping; implementing a transactional execution flag representing a processor core guaranteeing the atomicity and coherency of the currently executed instructions; implementing a transactional footprint, which keeps the address of each cache line that was used by the processor core; implementing a reference model, which operates on every cache line and keeps a set of timestamps for every cache line; implementing a core observed timestamp representing a global timestamp, which is the oldest construction date of data used before; implementing interface events; and reporting an error whenever a transaction end event is detected and any cache line is found in the transactional footprint with an expiration date that is older than or equal to the core observed time.