It will also include mount, dismount tests, it will include handling issues based on combinations and hardpoint placement, it includes emissions and RF leak tests, it includes catastrophic tests etc...... it includes comprehensive testing on various STANAG compliance vectors, it includes working off other allied data for verification and validation, it includes host nation certification issues.Some of the DefPros could likely explain it better than I, but weapons integration includes work to make sure that an aircraft's avionics can communicate with a missile for guidance, queing, launch command etc. It also includes trials to ensure weapons launch and clearance from the hardpoint/rail and away from the aircraft. Different missile types, having different weights and aerodynamic properties can behave differently during launch and in flight even if they are otherwise similar.
-Cheers
weapons testing is exhaustive. in fact the RAAF used to have a couple of test aircraft which were pulled from active service just to weapons test and validate combinations of sensors and systems. atypically its the first few aircraft of the order which end up with that lucky job.