Testing is not an issue because french and Brazilian navies already ordered F21 HWTs.The only question is ... Whats the Timeline are we looking at ? atleast for the F21 ie when can see the test, procurement and induction?
The F21 was developed as a serious counterpart and replacement for Black Shark torpedo. The F21 shares too many similarities with the Black Shark, including an electric motor driven by an aluminium silver-oxide battery.
For procurement and Induction: Its developmental trials are recently completed and 2 months ago, DCNS also offered it for IN's subs (scorpene class). So, it should not take more time to seal the deal. Most possibly, we will have F21 deal clubbed with the P75 extension (3 more scorpene class subs) in near future.