Converted balancer and backend to APIcast::Blackbox

[hector-vido]

I just converted t/backend.t and t/balancer.t to Test::APIcast::Blackbox.

This is probably an almost useless modification but if this is right, I can convert the more complex other ones.

Thanks!

[tkan145]

I wonder if we should delete this file because it really doesn't check anything.
cc @eguzki

[eguzki]

APIcast has configured a virtualhost backend, listening on 8081 and configured with conf.d/backend.conf. Not really used in production, but widely used in dev environments to mock backend and in the tests environments.

It makes sense to me to test that this virtualhost backend exists and returns what the mocked backend does, which is return a 200 OK with the body transactions authrep!

The other alternative is to remove the virtualhost backend and run some mock server in another container for tests. Then it would make sense to remove this test IMO.

Anyway, the new implementation of this backend.t is not testing the backend virtualhost. The request should hit the backend virtualhost directly.

[hector-vido]

@eguzki or @tkan145 any ideas on how to add a different port in the --- request section?
Since the port is randomized in Test/APIcast/Blackbox.pm I can't find a way to talk directly with the backend listening in 8081.
Don't know if this is the right path, but I added a section for sites_d:

--- sites_d
server {
  listen *:8081;
  server_name backend;
  include "/opt/app-root/src/gateway/conf.d/backend.conf";
}

It is working from outside the test script.

[tkan145]

This test is covered in #1416 . A small suggestion is to check existing PR(s) to avoid duplicating efforts. Good work on this one though.