Should you disconnect battery when load testing?

I'm curious, when it comes to load testing, is it necessary to disconnect the battery? I've heard conflicting opinions on the matter and I'm not sure what the best practice is. On one hand, some argue that disconnecting the battery can prevent potential damage to the electrical system during testing. On the other hand, others claim that it's not necessary and can actually hinder the accuracy of the test results. So, what's the verdict? Should I disconnect the battery when performing load testing, or is it SAFE to leave it connected?