Gossipsub: test extension

[MarcoPolo]

for interop testing

[ppopth]

I'm not sure what you are testing with this extension. What is your assert clause?

[MarcoPolo]

We should see the (empty) test extension being sent and received.

[raulk]

Is there a reason this cannot be a test vector under the extensions spec?

[MarcoPolo]

Is there a reason this cannot be a test vector under the #684?

My understanding of test vectors comes from using them in deterministic functions. For example, given some input a certain hash function should return some output. What would a test vector look like for this?

Another point is that the Extensions spec doesn't need to know about this extension at all (except as a registry of code points). This is the first example of an extension, and we don't need to treat it differently than any future extension.

[MarcoPolo]

We have two implementations of this in Rust and Go :)

[raulk]

My point is that this isn't useful as a standalone spec. And if the only reason it exists is for testing another spec, it should be a test harness under that spec, accompanied by the relevant test vectors.

[MarcoPolo]

Is the difference whether this is inlined in the extensions file or a separate file? I'd argue it's a better example if it's a separate file like any other extension would be.