How to efficiently find the breaking dependency

Hi!
Suppose I have a package A that I wrote myself, and I add it to a separate project environment B. I test A in A by running

using Pkg
Pkg.activate("A/")
Pkg.test("A")

and the tests fail. However, if I do the same thing but instead I activate B/ the tests run to completion.

Some of the dependency versions in B/Manifest.toml are different than in A/ so I’m lead to believe that it’s a version difference that’s causing the difference.

This bring me to my question:

TL;DR How do I bisect the difference between two Manifest.toml's efficiently to see which dependency version breaks one package/environment.