itest: add integration tests for integrated and remote modes

[guggero]

This PR adds a full integration test suite for testing the different proxy and authentication modes of the built-in proxy.

[Roasbeef]

Great set of initial test coverage!

This'll enable us to more easily test the final bundle to make sure we haven't introduced any breaking changes across the set of daemons we package, in both the remote and integrated mode.

Did an initial pass, main question is w.r.t the first few commits: is there anything fundamental preventing us from just using the lnd/lntest package as is and not copying over all the structs? I ask as there're a few updates to the lntest package itself queued up as lnd PRs, and ideally we can just update our commit hash here vs needing to manually cherry-pick the set of changes.

[ellemouton]

tAck 🚀 Awesome auth coverage!

One thing i noticed was that make itest-only only works if make build-itest was run previously (ie the btcd-itest, litd-itest & lnd-itest binaries have been built already). So maybe building these binaries should be extracted into their own make file func so that both those methods can call it?

[guggero]

Thanks for the review and feedback. I'm going to look into back-porting some of the custom stuff we need to make a harness for litd. Not sure if making the lnd harness more generic is worth the effort vs. having a copy of some of the code.

[Roasbeef]

Is this ready for another round of review? Want to make sure we're able to have proper itest coverage for the set of pending PRs that modify authentication.

[guggero]

Yes, it's ready for another round. But merging is now blocked by the release of lnd v0.14.2-beta because we need to include lightningnetwork/lnd#6139 and don't want to bump lnd to a non-tagged version.

[lightninglabs-deploy]

@guggero, remember to re-request review from reviewers when ready

[guggero]

I refactored this PR to re-use some of the structs from lntest. The rest is too lnd specific to be re-used without a huuuge refactor in the lnd repo.

[ellemouton]

tACK 🚀 although , my comment from before remain. Cant run the tests with make itest-only without first having run make itest which does the whole app build first. This is because make itest doesnt build the required btcd & lnd binaries by itself. Maybe it should?

[guggero]

tACK rocket although , my comment from before remain. Cant run the tests with make itest-only without first having run make itest which does the whole app build first. This is because make itest doesnt build the required btcd & lnd binaries by itself. Maybe it should?

The itest-only goal is only meant as a shortcut if you changed something in the tests only and don't want to re-compile the whole UI and dependencies. You need to run make itest initially, the same way we do it in lnd.

[Roasbeef]

LGTM 🐡