Use $callers to use expectations made in the calling process

[axelson]

My first implementation passed the result of Process.get(:"$callers") in to the server for processing but it felt cleaner to do that call in Mox itself.

Questions:

• How should we stop the new tests from running when Elixir < 1.8?
  • We could do feature detection by spawning a task and checking if it has $callers set?
    • I didn't like this initially but I'm coming around to it. We could even use the same function in assert_default_raise/2
  • Use an exunit tag and exclude it on some runs?
  • Direct version detection with System.version/0
• Should we add a test that uses spawn directly and assert that that still fails?
• Is $callers documented anywhere besides the Elixir 1.8 release notes?

[josevalim]

1. Let’s do a version check that sets the tag 2. No need 3. I think only there but that’s a good point. It should be documented elsewhere.

…

-- *José Valim* www.plataformatec.com.br Skype: jv.ptec Founder and Director of R&D

[axelson]

Okay, updated with a version check to set the tags to exclude.

[josevalim]

I think we should actually pass a list to the server and start looking up from head to tail. :)

[axelson]

Okay makes sense, I think we can treat self() as the first in the list of $callers and pass that whole list to the server. Then on the server we can check for any allowances set in the list of the pid's, falling back to the last entry in the passed in callers. I'll work on that tonight/this weekend.

[josevalim]

Instead of using assert_default_raise, we should rather change to a spawn_link or call Process.delete(:"$callers").

[josevalim]

Perfect. Although I think we should get the first entry (self()) in case of no matches (the current behavior). -- *José Valimwww.plataformatec.com.br <http://www.plataformatec.com.br/>Founder and Director of R&D*

[axelson]

I still need to fix up the assert_default_raise in the tests but I've updated the main check in server.ex to reflect "Although I think we should get the first entry (self()) in case of no matches (the current behavior)."

But isn't defaulting to the last caller (which will be the test process in these cases) cleaner?

    owner_pid = Enum.find_value(caller_pids, List.last(caller_pids), fn caller_pid ->
      state.allowances[caller_pid][mock]
    end)

[josevalim]

But isn't defaulting to the last caller (which will be the test process in these cases) cleaner?

I don't think it matters in the current code because the only scenario where it will use the default is when we don't have any allowances or expectations and that means both first or last will fail anyway?

[josevalim]

❤️ 💚 💙 💛 💜

[axelson]

Awesome, thanks!