Testing mechanism needs to use CaptureLog

[DavidAntaramian]

We can use https://hexdocs.pm/ex_unit/ExUnit.CaptureLog.html#content to capture logs, but for some reason it's outputting ANSI data in the log data when it shouldn't be. Once that's resolved, this should resolve a lot of issues around testing methods.

[mitchellhenke]

Does https://github.com/timberio/timber-elixir/blob/master/test/support/test_logger_backend.ex solve this?

[DavidAntaramian]

@mitchellhenke Not quite. Your change allows us to test what is received from Logger calls. What I want to be able to test here is the output we generate via our formatter. More like a full integration test.

More directly, I want to test that, given:

ip_address = "127.0.0.1"
port = 61248
session_id = "gzs78135"
Timber.add_context(remote_peer: %{ip_address: ip_address, port: port, session_id: session_id})
Logger.info fn ->
  "Timed out while waiting for data from remote peer"
end

the output (somewhat) matches:

Timed out while waiting for data from remote peer @metadata {"level":"info","dt":"2018-04-27T16:19:57.982531Z","context":{"custom":{"remote_peer":{"session_id":"gzs78135","port":61248,"ip_address":"127.0.0.1"}}},"$schema":"https://raw.githubusercontent.com/timberio/log-event-json-schema/v3.1.1/schema.json"}

Granted that matching output like that is really difficult 😕 The key though is to have tests that ensure that changes don't break the core functionality.

[mitchellhenke]

ah okay, darn. Thanks for the explanation