I’m trying to mock ExTwitter during tests, I’m using GitHub - dashbitco/mox: Mocks and explicit contracts in Elixir · GitHub for that. In my code I use a config variable to do the Dependency Injection, like this: config :my_app, # DI twitter_client: MyApp.TwitterClient I’ve defined my mock in…

[image] hubertlepicki: It’s not supposed to define new behaviours at compile time. Rather that it should create behaviour-compatible mocks based on already compiled modules. If you call Mox.defmock at compile time, which you do if you put it in the body of a file covered by elixirc_paths, the…

The Mox documentation suggests putting the Mox.defmock calls in test/test_helper.exs, that’s because the test helper is evaluated after all files are compiled. When you put the calls in the body of a compiled file it will try to check the mocked module is available at compile time which is a race co…

This is actually incorrect, and also something you probably don’t want to do as you will lose compile-time compatability check of behaviors. The problem is slightly different - i.e. the behavior is not properly specified here. I will publish a pull request for your repo @alex88 in a few mins to sho…

That’s because there is no order in the compilation process? Anyway, having the mocked module in the test config, when I move the mock into test_helper generates: warning: function MyApp.Mocks.TwitterClient.configure/2 is undefined (module MyApp.Mocks.TwitterClient is not available) lib/my_app/s…

hold on I’m investigating, some voodoo is going on here :smiley:

Sure, just wanted to share all I tried at this point :slight_smile:

[image] alex88: That’s because there is no order in the compilation process? Yes, modules will be compiled in the correct based on the calls or requires that is made in compile time. If you call a module at compile time the calling module will wait until the callee is compiled. If it’s suppo…

It’s not supposed to define new behaviours at compile time. Rather that it should create behaviour-compatible mocks based on already compiled modules, but you are right, it should be Code.ensure_compield?

Yes, you are right ref the cause of the issue.

I can confirm that changing from Code.ensure_loaded? to Code.ensure_compiled? fixes the issue while compiling and the app tests passes

I am trying to figure out why this is not happening on the app I am using mox in. But I guess it simply boils down to me being lucky and compilation order being luckily correct for me. I submitted a pull request and this should be resolved in next version :).

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Compilation order during tests

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hubertlepicki October 19, 2017, 6:38pm 16

Thank you both @alex88 for reporting the issue and @ericmj for finding the solution <3