Extract Test Setup Into Functions

Use this skill whenever you're writing or reviewing a test in this repo's tests/* test apps and you're about to share setup or teardown across more than one test() in the same module(name, function (hooks) {...}) block.

Steps

1. Don't register shared setup with hooks.beforeEach, and don't register shared teardown with hooks.afterEach. Both run unconditionally for every test() in the module, so a test that doesn't need that setup still pays for it — often a full Store with schemas and request handlers.

2. Write a plain function instead (module-scoped, or shared across files via its own module) and have each test that actually needs the setup call it explicitly, at the top of the test body:

   function setupStore() {
     const store = new Store();
     store.schema.registerResources([UserSchema]);
     return store;
   }
   
   module('widget updates', function () {
     test('creates a widget', function (assert) {
       const store = setupStore();
       assert.ok(store);
     });
   
     test('is unaffected by widget creation', function (assert) {
       // never calls setupStore() — pays nothing for it
       assert.ok(true);
     });
   });

3. If every single test in the module genuinely needs the same setup with no variation, a beforeEach isn't "wasteful" in the sense this skill cares about — but an extracted function called from each test still keeps the option open for a later test that doesn't need it, without a rewrite. Prefer the function either way.

4. setupTest(hooks)/setupRenderingTest(hooks) themselves are fine to keep — they're a single call, not a hooks.beforeEach/hooks.afterEach registration, and they wire up the test framework's owner rather than any test-specific state.

5. eslint-plugin-warp-drive's no-test-module-hooks rule (part of its recommended-internal ruleset) flags hooks.beforeEach/hooks.afterEach for exactly this reason. It runs as an error in tests/core's lint config; other, older test apps still have pre-existing hooks it hasn't been safe to flip to an error for yet, so it runs there as a warning instead while they get migrated incrementally. Don't add new hooks.beforeEach/hooks.afterEach usage to any of them, warning or not.

Why

A test suite this large runs its setup cost multiplied by however many tests share it. A beforeEach that builds a Store, registers schemas, and wires up request handlers runs that full cost before every single test in the module — including ones that only need a fraction of it, or none of it. An extracted function only runs, and only costs anything, for the tests that call it.