For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Get an USB 3.1 stick (64-128GB) and install macOS (e.g. Mojave) on it; use another good working macOS.
Install there any test software you need.
Then boot the problematic machine with it.