"pagesize" in SAT is just the size of the block data filled with a single pattern and tracked with metadata. The size was chosen more or less arbitrarily. big enough to not have too many pages' metadata to store, but small enough to have a variety of patterns.
"blocksize" is the size passed into the memcopy routine and is also pretty arbitrary. Neither of these are related to the OS or disk concepts of block or pages, and the values shouldn't affect test coverage or functionality much.