Hello everyone,

I wrote a Mix.Task that’s supposed to be run in a specific environment (:test) and nowhere else.
The task uses dependencies that are present only in the test environment.

I can set preferred_cli_env to make sure that the task automatically runs in the test environment when I invoke it, so that’s good.

However, when I compile my app in another environment (e.g. :dev) mix will try to compile that task, resulting in errors or at the very least compiler’s warnings due to the missing dependencies.

Is there an elegant way to solve this problem? I can think of a few options:

• Make the test-only dependencies used by the task available in all environments
• Enclose the code in my task in a huge if Mix.env() == :test do ... end clause
• Split tasks into directories: (i.e. task/test, task/dev etc.) and play around with the elixirc_paths option to disable compilation in specific environments

The last option is the only one appealing to me, but I think elixirc_paths only accepts a list of directories, and since lib is already in there, the tasks would have be moved out of lib. I wish there was a way to selectively exclude a directory, or even better a single file, but I believe that’s not possible.

Any ideas? Thank you very much in advance!