The DDoS attack against your network is irrelevant. It's the mitigation that's critical.
With thousands of variations of DDoS attacks and new ones popping up constantly, appropriate testing is critical. That’s why knowledge of the interaction between attacks and mitigation needs to be the starting point for effective DDoS testing.
Make sure your mitigation systems work, no matter the types of attacks. Instead of testing for varied attack vector, test for DDoS Mitigation to make sure it works as required all the time.