Dependencies on test-only behaviors

[jesperes]

In order to get behavior modules to build in before their uses, it is recommended (if I understand correctly) that the application to which the behavior belongs is added to the applications field the *.app.src file of the application which uses it. However, we have a case where we have behaviors which are only used during testing, and are thereby not supposed to be present at runtime. How can I make rebar3 build the applications in the correct order without modifying the *.app.src file?

[ferd]

The inclusion of applications in the {applications, ...} tuple was a workaround that should no longer be required in Rebar 3.14+ since we reworked things to do full static analysis of applications an behaviours to find compile-time dependencies and handle them distinctly from runtime dependencies.

That being said, if the behaviour is included in the main (non-test) application and it relies on apps visible only during tests, then yeah that's gonna be a problem because it will sometimes be compiled without the test dependencies being present.

[jesperes]

Hm. I'm using 3.14.2 something and seeing several cases of behavior modules missing if I don't add their applications to {applications, ...}.

Many of our applications are split into src/ and test/ where test/ is only built in test configurations (I'm in the process of figuring out how this is supposed to map to rebar3 concepts). Stuff in test/ is never included in our production packages, but they do have dependencies on applications which are only present when building test configurations (e.g. a test_suite behavior which resides in a test_util application).

But if these behavior dependencies should be detected automatically, then that is of course better.

[ferd]

They should be detected automatically, but that will depend on configured directories (i.e. see https://www.rebar3.org/docs/configuration/configuration/#directories to see when they're picked up and under which profiles). You might need to change project_app_dirs to contain "test/" in the test profile and whatnot.

[jesperes]

Ok, thanks, that is good to know.