fix(multistream-select): remove cyclic dependency to libp2p-core

[thomaseizinger]

Description

All of the removed dev-dependencies are only for testing the upgrade procedure in libp2p-core. Ironically, this test does not use a single API of multistream-select. Thus, this test is simply misplaced in this crate. If we wanted to retain it, it should probably go into libp2p itself as that one already depends on all required crates.

Related: #4053.

Notes & open questions

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[mxinden]

With #3563 in mind, I am fine moving forward here. Agreed with your argument, that this is already tested through other tests in the workspace.

For the lack of a better term, I would call this a hierarchy-violating test, i.e. a test that needs a downstream crate to function. I wonder whether we should consider such tests a code smell across the code base.

[thomaseizinger]

For the lack of a better term, I would call this a hierarchy-violating test, i.e. a test that needs a downstream crate to function. I wonder whether we should consider such tests a code smell across the code base.

We had the same issue in the past with transport crates using libp2p-swarm.

I consider this an anti-pattern. IMO, we should look at crates individually and test their APIs regardless of how they are used in upper layers.