testing

name	testing
description	Write or repair Elixir tests with ExUnit, sandbox isolation, async reliability, Mox, ExMachina, and LiveViewTest. Use for test files, test setup, or failing/flaky tests. NOT for investigating an application bug outside the test suite.
effort	medium
user-invocable	false
paths	["test/**/*_test.exs","test/support/**/*.ex","**/*factory*.ex"]

Elixir Testing Reference

Ash projects: Use DataCase with Ash.Test helpers; test actions via domain code interfaces, not direct Repo calls. See ash-framework skill.

Quick reference for Elixir testing patterns.

Iron Laws — Never Violate These

1. ASYNC BY DEFAULT — Use async: true unless tests modify global state
2. SANDBOX ISOLATION — All database tests use Ecto.Adapters.SQL.Sandbox
3. MOCK ONLY AT BOUNDARIES — Never mock database, internal modules, or stdlib
4. BEHAVIOURS AS CONTRACTS — All mocks must implement a defined @callback behaviour