How can you do a full range memory test on an SRAM test on the SRAM your application is using?

Working on a bear metal application in a Nios II embedded processor. A requirement of the product is that it does a full range memory test of the SRAM which the application code uses once up and running.

How can I do this? Clearly, I can't blindly just setup a pointer before main() and start writing / reading test patterns. Is there a way to run a "pre-application" before any of the application code variables are setup for example.

Thanks!