I’m going through the “Elixir For Programmers” course by Dave Thomas, which uses a simple game as didactic example.

I have written some unit tests for the game, extracted a TestPlayer module with some helper functions, and figured out I could have it loaded by placing it in test_helper.exs (placing it in its own file test_player.ex was like not having written it). Later I discovered that ElixirLS (with VSCode) seemed to ignore the contents of test_helper.exs: jump to definition doesn’t work.

I decided to try to extract the module again in its own file to se if it was going to make ElixirLS happier: test/test_helper/test_player.exs first but file compilation failed, then changed to .ex and still didn’t work.

So I wonder if I can define helper modules in their own files somewhere under the test folder and, ideally, have them loaded both when testing and by ElixirLS?

I can imagine projects where test-helpers would make test_helper.exs very large if that’s the only place where they can be defined,

Skimming through three books: Elixir in Action, Programming Elixir 1.6, Testing Elixir; didn’t answer my question.
On Testing Elixir at p.41 I found a test-double defined in integration_tests/soggy_waffle/fake_weather_api.ex; but that integration_tests folder seems non-Mix compliant, it leaves me wondering where they’d actually put it in a project, anyway my .ex file placed under the test folder were ignored.