I'm using a pretty old library to make server requests which is not properly tested and it not really matching nowadays requirements, so the plan is to migrate to a new one over the next release. So the idea is to plan a migration testing suite in order to make the transition painless.
The thing is, the new library works in a completely different way, and the migration testing suite would apparently need to be fully changed (which makes the whole purpose of it a little bit less interesting).
Does it make sense to have a migration testing suite, if the new library can't use that one? Does it make sense to create an intermediate migration testing suite (if that's ever possible) which can't test everything properly, but can give us a sense of security?