1. A method for testing the validity of shared data in a multiprocessing system, the method comprising: receiving at a first central processing unit a list of fetch and store instructions associated with blocks in a shared memory location, the list including: a data value, a central processing unit identifier and a relative order associated with the instructions, wherein: one of said data values associated with one of said instructions was stored by a memory-to-memory, memory-to-register or register-to-memory operation; and one of said central processing unit identifiers associated with one of said instructions is an identifier corresponding to one of a plurality of central processing units that have access to said shared memory location including said first central processing unit; performing a fetch operation at a block in said shared memory location from said first central processing unit; receiving fetched data at said first central processing unit in response to said performing, wherein said fetched data was stored by one of said plurality of central processing units; verifying that said fetched data conforms to a block concurrency rule in response to said list; and checking that said fetched data conforms to a serialization rule in response to said list.