Formatting a drive in DOS and Windows tests the entire storage area for bad sectors. Any bad sectors found are reported and recorded in the new FAT so that the operating system does not use them.
Formatting actually doesn't destroy the physical data during this test, it just creates a new, blank FAT, rendering the previous data irretrievable by normal means.
So you can just partition and format your drive if you want to test it for bad sectors.
Modus.