ehoandClaude Sonnet 5
a82332fa20
Writes up the principle behind WP-70's three tracks ("build test data
through the same door production code uses") as ADR-0006, with a decision
table for which fixture idiom fits which test type. Updates the
test-strategy skill (adds the Fixtures rule, fixes its stale pre-monorepo
src/app/... worked-example paths) and the shared Storybook testing.mdx page
to match. Closes WP-70 with the signatures/counts as actually shipped.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
79 lines
3.5 KiB
Markdown
79 lines
3.5 KiB
Markdown
---
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name: test-strategy
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description: Place tests the house way — Vitest specs co-located by layer (pure domain, no TestBed; parse* trust boundaries; thin UI via Storybook a11y). Use whenever adding a spec or deciding what to test.
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---
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# Test strategy (test where it's pure)
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Push logic down to where it's pure, test it there directly, keep the layers above thin.
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No `TestBed` for domain. Never assert on user-facing copy.
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## Rules
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- **`domain/` + any pure logic → required spec.** Reducers, combinators, `visibleSteps`,
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policies, parsers. Import the function and call it — no Angular, no `TestBed`.
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- **Value-object parser → happy path + normalisation + each rejection.** Assert on the
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`Result` discriminant (`.ok`) and the parsed value, **not** the error message.
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- **`infrastructure/` `parse*` (trust boundary) → required spec.** Accept a valid DTO;
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reject `null`, `{}`, and malformed shapes. Name it `describe('… (trust boundary)')`.
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- **`application/` stores/commands → spec** the pure reduce + optimistic
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begin→confirm/rollback + the command `Result`.
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- **`ui/` → Storybook story, not a component test.** Axe runs on every story; add a `play`
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only for wiring axe can't see.
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- **Never assert on `$localize` copy.** It changes per locale/edit — assert on the
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`Result`, the value object, or the message id.
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- **Fixtures go through the production door, never a hand-built literal** (ADR-0006).
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Replay real `Msg`s through the real `reduce` (`given(reduce, initial)(...msgs)`) for a
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state machine; `unwrapOk(parseX(raw))` for a value object; a type-state builder
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(`Given.Concept().Submitted()...`) for a backend aggregate with an ordered lifecycle.
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The one deliberate exception is a trust-boundary `parse*` spec, below — there the fixture
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must be a raw, possibly-malformed literal, because the test's whole point is "what if this
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shape is wrong." See ADR-0006's decision table for which idiom fits which test type.
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## Skeleton
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Co-locate `*.spec.ts` next to the unit, in the same layer folder:
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```
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<context>/domain/<thing>.spec.ts # pure — no TestBed
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<context>/domain/value-objects/<vo>.spec.ts # parser: ok + normalise + each reject
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<context>/infrastructure/<x>.adapter.spec.ts# parse* trust boundary
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<context>/application/<store|command>.spec.ts
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```
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Minimal parser spec:
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```ts
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import { describe, it, expect } from 'vitest';
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import { parseThing } from './thing';
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describe('parseThing', () => {
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it('accepts + normalises', () => {
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const r = parseThing(' raw ');
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expect(r.ok).toBe(true);
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if (r.ok) expect(r.value).toBe('RAW');
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});
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it('rejects malformed', () => {
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expect(parseThing('').ok).toBe(false); // asserts the tag, not the copy
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});
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});
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```
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## Worked examples
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- `apps/ssp/src/app/registratie/domain/value-objects/postcode.spec.ts` — parser style.
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- `apps/ssp/src/app/registratie/infrastructure/brp.adapter.spec.ts` — trust boundary (`null`/`{}`).
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- `apps/ssp/src/app/registratie/domain/registratie-wizard.machine.spec.ts` — pure reducer.
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- `libs/shared/src/testing/{machine,remote-data,value-object}.ts` — the shared fixture
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helpers (ADR-0006); `apps/ssp/src/app/herregistratie/domain/intake.testing.ts` — a
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per-context wrapper (`givenIntake = given(reduce, initial)`); `intake.acceptance.spec.ts`
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— a full journey expressed as one replayed message sequence.
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## Verify
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```bash
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npm test # Vitest (ng test — no vitest.config)
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npm run test-storybook # axe over every story (UI a11y gate)
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cd backend && dotnet test # backend rule + endpoint + golden tests
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```
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