As much as i like the idea of auto generated data it can get very complicated.
We use a depersonalised copy of the customer data.
we have something like 600 tables in out current database and depending on how the customer has configured the system can make a big difference to what data goes into the table and what tables are even updated.
That is not even taking into account the fact that over time the data in the tables tends to change. New fields and tables are added and most of the time for existing records these are NOT populated (what to put into them) so you have to test all the edge cases.