elixir_ci.mdc

---
description: Use when running tests, fixing CI failures, checking code coverage, formatting issues, or database test problems in Elixir projects
globs:
alwaysApply: false
---
- Run `make ci` to make sure all the changes are valid.
- Run `mix format` in case there are formatting issues.
- There's no need to prepend `mix test` command with `MIX_ENV=test`.
- Run `mix coveralls` and `mix coveralls.detail` to find out which code needs to be covered with tests.
- While fixing tests, you can use mix test --failed to run only previously failed tests.
- Never cheat by hardcoding values that are fit only for our tests to pass.
- To check code coverage run `mix coveralls.details` (e.g. `mix coveralls.detail test/my_app/processor_test.exs --filter processor`)
- Running `mix help <command>` can give you info on available options.
- If tests fail due to database schema inconsistencies, missing columns, or seed data interference, reset the test database with `MIX_ENV=test mix ecto.drop`.
- `mix test` will automatically recreate and migrate the database after dropping it.