refactor(specs): replay real messages in 4 machine specs (RB-31)

Four machine specs built their starting state with a hand-rolled object
literal instead of replaying real Msgs through the real reduce, the
exact anti-pattern ADR-0006 section 2 forbids. Three of the four also
hardcoded errors: {}, a shape the reducer might never actually produce.

intake.machine.spec.ts now imports the existing givenIntake from
intake.testing.ts (previously used only by intake.acceptance.spec.ts).
Three new one-line *.testing.ts files export the same given(reduce,
initial) wrapper for registratie-wizard, besluit, and brief. Every old
literal helper (answering, invullen, editingWith, loaded) is replaced
by a message replay that reaches the same state.

Two tests in registratie-wizard.machine.spec.ts asserted a cursor value
the real reducer cannot reach (cursor 2 with no diploma chosen yet,
which requires a diploma to already be set). Both are re-pointed at the
reachable cursor-1 equivalent; submit() validates the whole draft
regardless of cursor, so no assertion changed. Recorded in
implementation/rb-31.md, not worked around.

No *.machine.ts reducer was touched. All four specs pass; npm run ci
is green (lint, typecheck, dep:check, format, tokens, seam, all four
test suites, both app builds, backend 293/293, api-client drift).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/behandelportal/src/app/behandeling/domain/besluit.machine.spec.ts

@@ -1,12 +1,7 @@
 import { describe, it, expect } from 'vitest';
 import { expectTag } from '@shared/testing/expect-tag';
-import { BesluitState, reduce, initial } from './besluit.machine';
-
-const editingWith = (besluit: string, toelichting = ''): BesluitState => ({
-  tag: 'Editing',
-  draft: { besluit, toelichting },
-  errors: {},
-});
+import { reduce, initial } from './besluit.machine';
+import { givenBesluit } from './besluit.testing';
 
 describe('besluit reduce', () => {
   it('SetField updates the draft while editing', () => {
@@ -15,17 +10,23 @@ describe('besluit reduce', () => {
   });
 
   it('Submit with no besluit chosen stays Editing and reports a field error', () => {
-    const s = reduce(editingWith(''), { tag: 'Submit' });
+    const s = reduce(initial, { tag: 'Submit' });
     expect(expectTag(s, 'Editing').errors.besluit).toBeTruthy();
   });
 
   it('Submit Afwijzen without a toelichting stays Editing and reports a field error', () => {
-    const s = reduce(editingWith('Afwijzen'), { tag: 'Submit' });
+    const editingAfwijzen = givenBesluit({ tag: 'SetField', key: 'besluit', value: 'Afwijzen' });
+    const s = reduce(editingAfwijzen, { tag: 'Submit' });
     expect(expectTag(s, 'Editing').errors.toelichting).toBeTruthy();
   });
 
   it('Submit Goedkeuren with no toelichting moves to Submitting (optional there)', () => {
-    const s = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const editingGoedkeuren = givenBesluit({
+      tag: 'SetField',
+      key: 'besluit',
+      value: 'Goedkeuren',
+    });
+    const s = reduce(editingGoedkeuren, { tag: 'Submit' });
     expect(expectTag(s, 'Submitting').data).toEqual({
       besluit: 'Goedkeuren',
       toelichting: undefined,
@@ -33,7 +34,11 @@ describe('besluit reduce', () => {
   });
 
   it('Submit Afwijzen with a toelichting moves to Submitting with the trimmed value', () => {
-    const s = reduce(editingWith('Afwijzen', '  niet erkend  '), { tag: 'Submit' });
+    const editingAfwijzenWithToelichting = givenBesluit(
+      { tag: 'SetField', key: 'besluit', value: 'Afwijzen' },
+      { tag: 'SetField', key: 'toelichting', value: '  niet erkend  ' },
+    );
+    const s = reduce(editingAfwijzenWithToelichting, { tag: 'Submit' });
     expect(expectTag(s, 'Submitting').data).toEqual({
       besluit: 'Afwijzen',
       toelichting: 'niet erkend',
@@ -41,24 +46,36 @@ describe('besluit reduce', () => {
   });
 
   it('SubmitConfirmed maps Submitting to Submitted', () => {
-    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const submitting = givenBesluit(
+      { tag: 'SetField', key: 'besluit', value: 'Goedkeuren' },
+      { tag: 'Submit' },
+    );
     expect(reduce(submitting, { tag: 'SubmitConfirmed' }).tag).toBe('Submitted');
   });
 
   it('SubmitFailed maps Submitting to Failed with the error', () => {
-    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const submitting = givenBesluit(
+      { tag: 'SetField', key: 'besluit', value: 'Goedkeuren' },
+      { tag: 'Submit' },
+    );
     const failed = reduce(submitting, { tag: 'SubmitFailed', error: 'boom' });
     expect(failed).toMatchObject({ tag: 'Failed', error: 'boom' });
   });
 
   it('Retry re-submits a failure', () => {
-    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const submitting = givenBesluit(
+      { tag: 'SetField', key: 'besluit', value: 'Goedkeuren' },
+      { tag: 'Submit' },
+    );
     const failed = reduce(submitting, { tag: 'SubmitFailed', error: 'boom' });
     expect(reduce(failed, { tag: 'Retry' }).tag).toBe('Submitting');
   });
 
   it('Reset returns to the initial editing state', () => {
-    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const submitting = givenBesluit(
+      { tag: 'SetField', key: 'besluit', value: 'Goedkeuren' },
+      { tag: 'Submit' },
+    );
     expect(reduce(submitting, { tag: 'Reset' })).toEqual(initial);
   });
 });

apps/behandelportal/src/app/behandeling/domain/besluit.testing.ts

@@ -0,0 +1,7 @@
+import { given } from '@shared/testing/machine';
+import { reduce, initial } from './besluit.machine';
+
+/** Replay real `BesluitMsg`s through the real `reduce`, starting from `initial`.
+    Pure TS only (no Angular) — domain/ stays framework-free (dependency-cruiser
+    `domain-is-pure`). See `libs/shared/src/testing/machine.ts`. */
+export const givenBesluit = given(reduce, initial);

apps/ssp/src/app/brief/domain/brief.machine.spec.ts

@@ -3,6 +3,7 @@ import { Besluit, Brief, BriefDecisions, BriefStatus, LibraryPassage } from './b
 import { RichTextBlock } from '@shared/kernel/rich-text';
 import { PlaceholderDef } from './placeholders';
 import { BriefState, reduce } from './brief.machine';
+import { givenBrief } from './brief.testing';
 
 const placeholders: PlaceholderDef[] = [
   { key: 'naam', label: 'Naam', autoResolvable: true },
@@ -64,15 +65,15 @@ const decisions: BriefDecisions = {
   canRevealBigNummer: true,
 };
 
-const loaded = (
-  status: BriefStatus = { tag: 'draft' },
-  sections?: Brief['sections'],
-): BriefState => ({
-  tag: 'loaded',
-  brief: briefWith(status, sections),
-  availablePassages: lib,
-  decisions,
-});
+// Replays a real `BriefLoaded` message through the real `reduce` (ADR-0006 §2)
+// instead of hand-assembling the 'loaded' state directly.
+const loaded = (status: BriefStatus = { tag: 'draft' }, sections?: Brief['sections']): BriefState =>
+  givenBrief({
+    tag: 'BriefLoaded',
+    brief: briefWith(status, sections),
+    availablePassages: lib,
+    decisions,
+  });
 
 const sectionBlocks = (s: BriefState, key: string) =>
   s.tag === 'loaded' ? s.brief.sections.find((x) => x.sectionKey === key)!.blocks : [];
@@ -128,12 +129,12 @@ describe('brief.machine reduce', () => {
 
   it('BesluitSelected deep-copies content — later library mutation does not leak in', () => {
     const passage = libPassage('intro', 'kern'); // shared → offered for any besluit
-    const st: BriefState = {
-      tag: 'loaded',
+    const st = givenBrief({
+      tag: 'BriefLoaded',
       brief: briefWith({ tag: 'draft' }),
       availablePassages: [passage],
       decisions,
-    };
+    });
     const s = reduce(st, besluit('positief'));
     // Mutate the source passage object after composition.
     (passage.content.paragraphs[0].nodes as { type: 'text'; text: string }[])[0].text = 'HACKED';

apps/ssp/src/app/brief/domain/brief.testing.ts

@@ -0,0 +1,7 @@
+import { given } from '@shared/testing/machine';
+import { reduce, initial } from './brief.machine';
+
+/** Replay real `BriefMsg`s through the real `reduce`, starting from `initial`.
+    Pure TS only (no Angular) — domain/ stays framework-free (dependency-cruiser
+    `domain-is-pure`). See `libs/shared/src/testing/machine.ts`. */
+export const givenBrief = given(reduce, initial);

apps/ssp/src/app/herregistratie/domain/intake.machine.spec.ts

@@ -2,7 +2,6 @@ import { describe, it, expect } from 'vitest';
 import { ok, err } from '@shared/kernel/fp';
 import { expectTag } from '@shared/testing/expect-tag';
 import {
-  Answers,
   initial,
   STEPS,
   lageUren,
@@ -15,14 +14,7 @@ import {
   reduce,
   IntakeState,
 } from './intake.machine';
-
-const answering = (answers: Answers, cursor = 0, scholingThreshold = 1000): IntakeState => ({
-  tag: 'Answering',
-  answers,
-  cursor,
-  errors: {},
-  scholingThreshold,
-});
+import { givenIntake } from './intake.testing';
 
 describe('STEPS (fixed) and inline questions', () => {
   it('always has the same three steps', () => {
@@ -31,12 +23,12 @@ describe('STEPS (fixed) and inline questions', () => {
 
   it('reveals the buitenland detail questions inline only when worked abroad', () => {
     // No new step; instead these fields become required within the buitenland step.
-    expect(next(answering({ buitenlandGewerkt: 'ja' })).tag).toBe('Answering'); // land/uren missing -> blocked
-    expect(
-      expectTag(next(answering({ buitenlandGewerkt: 'ja' })), 'Answering').errors.land,
-    ).toBeTruthy();
-    expect(next(answering({ buitenlandGewerkt: 'nee' })).tag).toBe('Answering'); // valid, advances (cursor moves)
-    expect(expectTag(next(answering({ buitenlandGewerkt: 'nee' })), 'Answering').cursor).toBe(1);
+    const abroad = givenIntake({ tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'ja' });
+    expect(next(abroad).tag).toBe('Answering'); // land/uren missing -> blocked
+    expect(expectTag(next(abroad), 'Answering').errors.land).toBeTruthy();
+    const domestic = givenIntake({ tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' });
+    expect(next(domestic).tag).toBe('Answering'); // valid, advances (cursor moves)
+    expect(expectTag(next(domestic), 'Answering').cursor).toBe(1);
   });
 
   it('reveals the scholing question only when NL-hours are below the threshold', () => {
@@ -49,9 +41,13 @@ describe('STEPS (fixed) and inline questions', () => {
     expect(lageUren({ uren: '1500' }, 1000)).toBe(false);
     expect(lageUren({ uren: '1500' }, 2000)).toBe(true);
     // And the threshold from state flows through submit:
-    const lowThreshold = submit(
-      answering({ buitenlandGewerkt: 'nee', uren: '1500', punten: '200' }, 0, 2000),
+    const lowThresholdState = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '1500' },
+      { tag: 'SetAnswer', key: 'punten', value: '200' },
+      { tag: 'SetPolicy', scholingThreshold: 2000 },
     );
+    const lowThreshold = submit(lowThresholdState);
     expect(lowThreshold.tag).toBe('Answering'); // scholing now required (1500 < 2000), unanswered → blocked
     expect(expectTag(lowThreshold, 'Answering').errors.scholingGevolgd).toBeTruthy();
   });
@@ -65,18 +61,21 @@ describe('navigation', () => {
   });
 
   it('Next advances once the step is valid', () => {
-    const s = expectTag(next(answering({ buitenlandGewerkt: 'nee' })), 'Answering');
+    const domestic = givenIntake({ tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' });
+    const s = expectTag(next(domestic), 'Answering');
     expect(s.cursor).toBe(1);
     expect(currentStep(s)).toBe('werk');
   });
 
   it('editing an answer leaves the cursor fixed (steps never collapse)', () => {
+    const atWerk = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'ja' },
+      { tag: 'SetAnswer', key: 'land', value: 'België' },
+      { tag: 'SetAnswer', key: 'buitenlandseUren', value: '300' },
+      { tag: 'Next' }, // buitenland step valid -> cursor 0 -> 1
+    );
     const edited = expectTag(
-      reduce(answering({ buitenlandGewerkt: 'ja' }, 1), {
-        tag: 'SetAnswer',
-        key: 'buitenlandGewerkt',
-        value: 'nee',
-      }),
+      reduce(atWerk, { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' }),
       'Answering',
     );
     expect(edited.cursor).toBe(1); // cursor untouched; only inline questions change
@@ -87,57 +86,86 @@ describe('navigation', () => {
   });
 
   it('gaNaarStap jumps back to an earlier step, clearing errors', () => {
-    const s = answering({ buitenlandGewerkt: 'nee' }, 2);
+    const s = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'Next' }, // cursor 0 -> 1
+      { tag: 'SetAnswer', key: 'uren', value: '4160' },
+      { tag: 'Next' }, // cursor 1 -> 2
+    );
     expect(expectTag(gaNaarStap(s, 0), 'Answering').cursor).toBe(0);
   });
 
   it('gaNaarStap ignores a same/forward jump and jumps outside Answering', () => {
-    const s = answering({ buitenlandGewerkt: 'nee' }, 1);
+    const s = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'Next' }, // cursor 0 -> 1
+    );
     expect(gaNaarStap(s, 1)).toBe(s); // same step -> no-op
     expect(gaNaarStap(s, 2)).toBe(s); // forward -> no-op
-    const submitting = submit(answering({ buitenlandGewerkt: 'nee', uren: '4160' }, 2));
+    const atReview = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'Next' }, // cursor 0 -> 1
+      { tag: 'SetAnswer', key: 'uren', value: '4160' },
+      { tag: 'Next' }, // cursor 1 -> 2
+    );
+    const submitting = submit(atReview);
     expect(gaNaarStap(submitting, 0)).toBe(submitting); // not Answering -> no-op
   });
 });
 
 describe('submit', () => {
   // High hours: no scholing question, so no punten is asked or collected.
-  const complete: Answers = { buitenlandGewerkt: 'nee', uren: '4160' };
+  const highUren = givenIntake(
+    { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+    { tag: 'SetAnswer', key: 'uren', value: '4160' },
+  );
 
   it('reaches Submitting ONLY with valid answers', () => {
     // Bad punten only blocks when scholing was followed (otherwise punten is ignored).
-    expect(
-      submit(
-        answering({ buitenlandGewerkt: 'nee', uren: '500', scholingGevolgd: 'ja', punten: 'x' }),
-      ).tag,
-    ).toBe('Answering');
-    const good = expectTag(submit(answering(complete)), 'Submitting');
+    const badPunten = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '500' },
+      { tag: 'SetAnswer', key: 'scholingGevolgd', value: 'ja' },
+      { tag: 'SetAnswer', key: 'punten', value: 'x' },
+    );
+    expect(submit(badPunten).tag).toBe('Answering');
+    const good = expectTag(submit(highUren), 'Submitting');
     expect(good.data.uren).toBe(4160);
     expect(good.data.punten).toBeUndefined(); // not collected without scholing
   });
 
   it('punten is required only when aanvullende scholing was gevolgd', () => {
     // scholing = ja but punten missing -> blocked on punten.
-    const missing = expectTag(
-      submit(answering({ buitenlandGewerkt: 'nee', uren: '500', scholingGevolgd: 'ja' })),
-      'Answering',
+    const scholingJaNoPunten = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '500' },
+      { tag: 'SetAnswer', key: 'scholingGevolgd', value: 'ja' },
     );
+    const missing = expectTag(submit(scholingJaNoPunten), 'Answering');
     expect(missing.errors.punten).toBeTruthy();
     // scholing = nee -> punten not required, submits without it.
-    expect(
-      submit(answering({ buitenlandGewerkt: 'nee', uren: '500', scholingGevolgd: 'nee' })).tag,
-    ).toBe('Submitting');
+    const scholingNee = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '500' },
+      { tag: 'SetAnswer', key: 'scholingGevolgd', value: 'nee' },
+    );
+    expect(submit(scholingNee).tag).toBe('Submitting');
   });
 
   it('low hours requires the scholing answer before submit', () => {
-    const noScholing = submit(answering({ buitenlandGewerkt: 'nee', uren: '500' }));
-    expect(noScholing.tag).toBe('Answering'); // scholing question is required, unanswered
-    const withScholing = expectTag(
-      submit(
-        answering({ buitenlandGewerkt: 'nee', uren: '500', scholingGevolgd: 'ja', punten: '200' }),
-      ),
-      'Submitting',
+    const lowUrenNoScholing = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '500' },
     );
+    const noScholing = submit(lowUrenNoScholing);
+    expect(noScholing.tag).toBe('Answering'); // scholing question is required, unanswered
+    const lowUrenWithScholing = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '500' },
+      { tag: 'SetAnswer', key: 'scholingGevolgd', value: 'ja' },
+      { tag: 'SetAnswer', key: 'punten', value: '200' },
+    );
+    const withScholing = expectTag(submit(lowUrenWithScholing), 'Submitting');
     expect(withScholing.data.aanvullendeScholing).toBe(true);
     expect(withScholing.data.punten).toBe(200);
   });
@@ -145,38 +173,36 @@ describe('submit', () => {
   it('does not require punten for a hidden question (WP-69 §6)', () => {
     // scholingGevolgd is a stale 'ja' from when uren was low, but uren is now above
     // threshold — the template hides the question, so punten must not be required either.
-    const good = expectTag(
-      submit(answering({ buitenlandGewerkt: 'nee', uren: '1500', scholingGevolgd: 'ja' })),
-      'Submitting',
+    const staleScholingNoPunten = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '1500' },
+      { tag: 'SetAnswer', key: 'scholingGevolgd', value: 'ja' },
     );
+    const good = expectTag(submit(staleScholingNoPunten), 'Submitting');
     expect(good.data.aanvullendeScholing).toBeUndefined();
   });
 
   it('drops punten when raising uren hides the question (WP-69 §6)', () => {
     // Same stale answer, but this time punten was also filled in while uren was low.
-    const good = expectTag(
-      submit(
-        answering({
-          buitenlandGewerkt: 'nee',
-          uren: '1500',
-          scholingGevolgd: 'ja',
-          punten: '150',
-        }),
-      ),
-      'Submitting',
+    const staleScholingWithPunten = givenIntake(
+      { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+      { tag: 'SetAnswer', key: 'uren', value: '1500' },
+      { tag: 'SetAnswer', key: 'scholingGevolgd', value: 'ja' },
+      { tag: 'SetAnswer', key: 'punten', value: '150' },
     );
+    const good = expectTag(submit(staleScholingWithPunten), 'Submitting');
     // ValidIntake stays honest: neither the stale 'ja' nor its punten leak through.
     expect(good.data.aanvullendeScholing).toBeUndefined();
     expect(good.data.punten).toBeUndefined();
   });
 
   it('resolve maps Submitting to Submitted on a successful submit', () => {
-    const submitting = submit(answering(complete));
+    const submitting = submit(highUren);
     expect(resolve(submitting, ok(undefined)).tag).toBe('Submitted');
   });
 
   it('resolve maps Submitting to Failed on a failed submit', () => {
-    const submitting = submit(answering(complete));
+    const submitting = submit(highUren);
     expect(resolve(submitting, err('boom')).tag).toBe('Failed');
   });
 });

apps/ssp/src/app/registratie/domain/registratie-wizard.machine.spec.ts

@@ -1,9 +1,8 @@
 import { describe, it, expect } from 'vitest';
 import { ok, err } from '@shared/kernel/fp';
-import { initialUpload } from '@shared/domain/upload.machine';
+import { given } from '@shared/testing/machine';
 import { expectTag } from '@shared/testing/expect-tag';
 import {
-  Draft,
   RegistratieState,
   STEPS,
   initial,
@@ -21,28 +20,50 @@ import {
   resolve,
   reduce,
 } from './registratie-wizard.machine';
+import { givenRegistratieWizard } from './registratie-wizard.testing';
 
-const invullen = (draft: Partial<Draft>, cursor = 0): RegistratieState => ({
-  tag: 'Invullen',
-  draft: { antwoorden: {}, ...draft },
-  cursor,
-  errors: {},
-  upload: initialUpload,
-});
+/**
+ * Every fixture below is built by replaying real `RegistratieMsg`s through the
+ * real `reduce` (ADR-0006 §2) — never a hand-assembled `RegistratieState`
+ * literal. Each helper reaches a named point in the wizard one transition at a
+ * time, so a spec can only assert on a state the reducer can actually produce.
+ */
+const toAdresValid = (): RegistratieState =>
+  givenRegistratieWizard(
+    {
+      tag: 'PrefillAdres',
+      straat: 'Lange Voorhout 9',
+      postcode: '2514 EA',
+      woonplaats: 'Den Haag',
+    },
+    { tag: 'SetCorrespondentie', value: 'post' },
+  );
 
-const validAdres = {
-  straat: 'Lange Voorhout 9',
-  postcode: '2514 EA',
-  woonplaats: 'Den Haag',
-  correspondentie: 'post' as const,
-  adresHerkomst: 'brp' as const,
-};
-const validDraft: Partial<Draft> = {
-  ...validAdres,
-  diplomaId: 'd1',
-  beroep: 'Arts',
-  diplomaHerkomst: 'duo',
-};
+const toBeroepStep = (): RegistratieState => reduce(toAdresValid(), { tag: 'Next' }); // cursor 0 -> 1, no diploma yet
+
+const toBeroepStepWithDiploma = (): RegistratieState =>
+  reduce(toBeroepStep(), { tag: 'KiesDiploma', diplomaId: 'd1', beroep: 'Arts', vraagIds: [] });
+
+const toControleStep = (): RegistratieState => reduce(toBeroepStepWithDiploma(), { tag: 'Next' }); // cursor 1 -> 2
+
+const toIndienen = (): RegistratieState => reduce(toControleStep(), { tag: 'Submit' });
+
+// A complete, valid draft assembled WITHOUT ever advancing the cursor. Setting a
+// field or choosing a diploma is never gated by cursor position, so this is a
+// real, reachable 'Invullen' state at cursor 0 — matching what `submit()`
+// (which validates the whole draft regardless of cursor) is exercised against
+// in the tests below.
+const toFullDraftAtCursor0 = (): RegistratieState =>
+  givenRegistratieWizard(
+    {
+      tag: 'PrefillAdres',
+      straat: 'Lange Voorhout 9',
+      postcode: '2514 EA',
+      woonplaats: 'Den Haag',
+    },
+    { tag: 'SetCorrespondentie', value: 'post' },
+    { tag: 'KiesDiploma', diplomaId: 'd1', beroep: 'Arts', vraagIds: [] },
+  );
 
 describe('STEPS (fixed)', () => {
   it('always has the same three steps', () => {
@@ -60,46 +81,55 @@ describe('navigation', () => {
   });
 
   it('Next advances once the adres step is valid', () => {
-    const s = expectTag(next(invullen(validAdres)), 'Invullen');
+    const s = expectTag(next(toAdresValid()), 'Invullen');
     expect(s.cursor).toBe(1);
     expect(currentStep(s)).toBe('beroep');
   });
 
   it('requires a valid e-mail only when the channel is email', () => {
-    const bad = expectTag(next(invullen({ ...validAdres, correspondentie: 'email' })), 'Invullen');
+    const withEmailChannel = givenRegistratieWizard(
+      {
+        tag: 'PrefillAdres',
+        straat: 'Lange Voorhout 9',
+        postcode: '2514 EA',
+        woonplaats: 'Den Haag',
+      },
+      { tag: 'SetCorrespondentie', value: 'email' },
+    );
+    const bad = expectTag(next(withEmailChannel), 'Invullen');
     expect(bad.errors.email).toBeTruthy();
     const good = expectTag(
-      next(invullen({ ...validAdres, correspondentie: 'email', email: 'a@b.nl' })),
+      next(given(reduce, withEmailChannel)({ tag: 'SetField', key: 'email', value: 'a@b.nl' })),
       'Invullen',
     );
     expect(good.cursor).toBe(1);
   });
 
   it('beroep step requires a chosen diploma', () => {
-    const noDiploma = expectTag(next(invullen(validAdres, 1)), 'Invullen');
+    const noDiploma = expectTag(next(toBeroepStep()), 'Invullen');
     expect(noDiploma.cursor).toBe(1);
     expect(noDiploma.errors.diploma).toBeTruthy();
-    const withDiploma = expectTag(next(invullen(validDraft, 1)), 'Invullen');
+    const withDiploma = expectTag(next(toBeroepStepWithDiploma()), 'Invullen');
     expect(withDiploma.cursor).toBe(2);
   });
 
   it('Back never goes below the first step and preserves the draft', () => {
     expect(back(initial)).toBe(initial);
-    const s = expectTag(back(invullen(validDraft, 2)), 'Invullen');
+    const s = expectTag(back(toControleStep()), 'Invullen');
     expect(s.cursor).toBe(1);
     expect(s.draft.beroep).toBe('Arts');
   });
 
   it('GaNaarStap only jumps backwards', () => {
-    expect(expectTag(gaNaarStap(invullen(validDraft, 2), 0), 'Invullen').cursor).toBe(0);
-    expect(expectTag(gaNaarStap(invullen(validDraft, 1), 2), 'Invullen').cursor).toBe(1); // forward jump rejected
+    expect(expectTag(gaNaarStap(toControleStep(), 0), 'Invullen').cursor).toBe(0);
+    expect(expectTag(gaNaarStap(toBeroepStepWithDiploma(), 2), 'Invullen').cursor).toBe(1); // forward jump rejected
   });
 });
 
 describe('adres origin (BRP vs handmatig)', () => {
   it('prefillAdres flags origin brp', () => {
     const s = expectTag(
-      prefillAdres(invullen({}), 'Lange Voorhout 9', '2514 EA', 'Den Haag'),
+      prefillAdres(initial, 'Lange Voorhout 9', '2514 EA', 'Den Haag'),
       'Invullen',
     );
     expect(s.draft.adresHerkomst).toBe('brp');
@@ -107,43 +137,38 @@ describe('adres origin (BRP vs handmatig)', () => {
   });
 
   it('editing a prefilled address field flips origin to handmatig', () => {
-    const prefilled = prefillAdres(invullen({}), 'Lange Voorhout 9', '2514 EA', 'Den Haag');
+    const prefilled = prefillAdres(initial, 'Lange Voorhout 9', '2514 EA', 'Den Haag');
     const edited = expectTag(setField(prefilled, 'woonplaats', 'Rotterdam'), 'Invullen');
     expect(edited.draft.adresHerkomst).toBe('handmatig');
   });
 
   it('typing an address with no BRP prefill yields handmatig', () => {
-    const s = expectTag(setField(invullen({}), 'straat', 'Kerkstraat 1'), 'Invullen');
+    const s = expectTag(setField(initial, 'straat', 'Kerkstraat 1'), 'Invullen');
     expect(s.draft.adresHerkomst).toBe('handmatig');
   });
 
   it('editing the e-mail field does not change the address origin', () => {
-    const prefilled = prefillAdres(invullen({}), 'Lange Voorhout 9', '2514 EA', 'Den Haag');
+    const prefilled = prefillAdres(initial, 'Lange Voorhout 9', '2514 EA', 'Den Haag');
     const edited = expectTag(setField(prefilled, 'email', 'a@b.nl'), 'Invullen');
     expect(edited.draft.adresHerkomst).toBe('brp');
   });
 
   it('a manually entered address still submits (only manual diploma is gated)', () => {
-    const s = submit(
-      invullen({
-        straat: 'Kerkstraat 1',
-        postcode: '1234 AB',
-        woonplaats: 'Utrecht',
-        correspondentie: 'post',
-        adresHerkomst: 'handmatig',
-        diplomaId: 'd1',
-        beroep: 'Arts',
-        diplomaHerkomst: 'duo',
-      }),
+    const manualAdres = givenRegistratieWizard(
+      { tag: 'SetField', key: 'straat', value: 'Kerkstraat 1' },
+      { tag: 'SetField', key: 'postcode', value: '1234 AB' },
+      { tag: 'SetField', key: 'woonplaats', value: 'Utrecht' },
+      { tag: 'SetCorrespondentie', value: 'post' },
+      { tag: 'KiesDiploma', diplomaId: 'd1', beroep: 'Arts', vraagIds: [] },
     );
-    const indienen = expectTag(s, 'Indienen');
+    const indienen = expectTag(submit(manualAdres), 'Indienen');
     expect(indienen.data.adresHerkomst).toBe('handmatig');
   });
 });
 
 describe('kiesDiploma', () => {
   it('derives the beroep from the chosen diploma and flags origin duo', () => {
-    const s = expectTag(kiesDiploma(invullen({}), 'd9', 'Verpleegkundige', []), 'Invullen');
+    const s = expectTag(kiesDiploma(initial, 'd9', 'Verpleegkundige', []), 'Invullen');
     expect(s.draft.diplomaId).toBe('d9');
     expect(s.draft.beroep).toBe('Verpleegkundige');
     expect(s.draft.diplomaHerkomst).toBe('duo');
@@ -152,7 +177,7 @@ describe('kiesDiploma', () => {
 
 describe('policy questions (geldigheidsvragen)', () => {
   it('a diploma with questions blocks Next until they are answered', () => {
-    let s = kiesDiploma(invullen(validAdres, 1), 'd2', 'Arts', ['nl-taalvaardigheid']);
+    let s = kiesDiploma(toBeroepStep(), 'd2', 'Arts', ['nl-taalvaardigheid']);
     const blocked = expectTag(next(s), 'Invullen');
     expect(blocked.cursor).toBe(1);
     expect(blocked.errors.antwoorden?.['nl-taalvaardigheid']).toBeTruthy();
@@ -161,7 +186,12 @@ describe('policy questions (geldigheidsvragen)', () => {
   });
 
   it('validateAll keeps only the answers to the questions that applied', () => {
-    let s = kiesDiploma(invullen(validAdres, 2), 'd2', 'Arts', ['nl-taalvaardigheid']);
+    // DRIFT (see rb-31.md): the old literal put the wizard at cursor 2 before any
+    // diploma was chosen. That combination cannot occur in the real reducer —
+    // advancing past 'beroep' (cursor 1 -> 2) requires a diploma to already be
+    // set. Replayed here at cursor 1 instead; submit() validates the whole draft
+    // regardless of cursor, so the assertion below is unaffected.
+    let s = kiesDiploma(toBeroepStep(), 'd2', 'Arts', ['nl-taalvaardigheid']);
     s = setAntwoord(s, 'nl-taalvaardigheid', 'ja');
     s = setAntwoord(s, 'stale', 'x'); // not in vraagIds
     const done = expectTag(submit(s), 'Indienen');
@@ -173,14 +203,16 @@ describe('manual diploma fallback', () => {
   const maxIds = ['nl-taalvaardigheid', 'diploma-erkend', 'toelichting'];
 
   it('KiesHandmatig flags handmatig with the maximal question set and no beroep yet', () => {
-    const s = expectTag(kiesHandmatig(invullen(validAdres, 1), maxIds), 'Invullen');
+    const s = expectTag(kiesHandmatig(toBeroepStep(), maxIds), 'Invullen');
     expect(s.draft.diplomaHerkomst).toBe('handmatig');
     expect(s.draft.beroep).toBeUndefined();
     expect(s.draft.vraagIds).toEqual(maxIds);
   });
 
   it('requires a declared beroep + all maximal questions before submit', () => {
-    let s = kiesHandmatig(invullen(validAdres, 2), maxIds);
+    // DRIFT (see rb-31.md): same unreachable cursor-2-before-diploma combination
+    // as above. Replayed at cursor 1; submit() is cursor-agnostic.
+    let s = kiesHandmatig(toBeroepStep(), maxIds);
     expect(submit(s).tag).toBe('Invullen'); // no beroep declared
     s = declareerBeroep(s, 'Fysiotherapeut');
     expect(submit(s).tag).toBe('Invullen'); // questions unanswered
@@ -193,11 +225,11 @@ describe('manual diploma fallback', () => {
 
 describe('submit', () => {
   it('stays in Invullen when the draft is incomplete (no diploma)', () => {
-    expect(submit(invullen(validAdres)).tag).toBe('Invullen');
+    expect(submit(toAdresValid()).tag).toBe('Invullen');
   });
 
   it('reaches Indienen with a complete, valid draft, carrying its data', () => {
-    const good = expectTag(submit(invullen(validDraft)), 'Indienen');
+    const good = expectTag(submit(toFullDraftAtCursor0()), 'Indienen');
     expect(good.data.beroep).toBe('Arts');
     expect(good.data.adres.postcode).toBe('2514 EA');
     expect(good.data.adresHerkomst).toBe('brp');
@@ -205,43 +237,18 @@ describe('submit', () => {
 
   it('resolve maps Indienen to Ingediend with the referentie', () => {
     const ingediend = expectTag(
-      resolve(submit(invullen(validDraft)), ok('BIG-2026-001')),
+      resolve(submit(toFullDraftAtCursor0()), ok('BIG-2026-001')),
       'Ingediend',
     );
     expect(ingediend.referentie).toBe('BIG-2026-001');
   });
 
   it('resolve maps Indienen to Mislukt on a failed submit', () => {
-    expect(resolve(submit(invullen(validDraft)), err('boom')).tag).toBe('Mislukt');
+    expect(resolve(submit(toFullDraftAtCursor0()), err('boom')).tag).toBe('Mislukt');
   });
 });
 
 describe('reduce (message-driven happy path)', () => {
-  // Each helper replays real messages through the real reducer up to the named
-  // point — no hand-assembled state literal — so each test below Givens its own
-  // starting point independently, one transition at a time.
-  const toBeroepStep = (): RegistratieState => {
-    let s: RegistratieState = initial;
-    s = reduce(s, {
-      tag: 'PrefillAdres',
-      straat: 'Lange Voorhout 9',
-      postcode: '2514 EA',
-      woonplaats: 'Den Haag',
-    });
-    s = reduce(s, { tag: 'SetCorrespondentie', value: 'post' });
-    return reduce(s, { tag: 'Next' });
-  };
-  const toControleStep = (): RegistratieState => {
-    const s = reduce(toBeroepStep(), {
-      tag: 'KiesDiploma',
-      diplomaId: 'd1',
-      beroep: 'Arts',
-      vraagIds: [],
-    });
-    return reduce(s, { tag: 'Next' });
-  };
-  const toIndienen = (): RegistratieState => reduce(toControleStep(), { tag: 'Submit' });
-
   it('adres and correspondentie set, Next advances from adres to beroep', () => {
     // Given the initial wizard.
     // When the adres is prefilled, correspondentie chosen, and Next dispatched...
@@ -279,7 +286,7 @@ describe('reduce (message-driven happy path)', () => {
   });
 
   it('SubmitFailed moves Indienen to Mislukt', () => {
-    const s = reduce(reduce(invullen(validDraft), { tag: 'Submit' }), {
+    const s = reduce(reduce(toFullDraftAtCursor0(), { tag: 'Submit' }), {
       tag: 'SubmitFailed',
       error: 'boom',
     });
@@ -287,7 +294,7 @@ describe('reduce (message-driven happy path)', () => {
   });
 
   it('Retry returns Mislukt to Indienen with the same data', () => {
-    const mislukt = reduce(reduce(invullen(validDraft), { tag: 'Submit' }), {
+    const mislukt = reduce(reduce(toFullDraftAtCursor0(), { tag: 'Submit' }), {
       tag: 'SubmitFailed',
       error: 'boom',
     });
@@ -310,7 +317,7 @@ describe('inline document upload (beroep step)', () => {
 
   it('routes Upload messages through the upload reducer', () => {
     const s = expectTag(
-      reduce(invullen(validDraft), {
+      reduce(toFullDraftAtCursor0(), {
         tag: 'Upload',
         msg: { type: 'CategoriesLoaded', categories: [cat] },
       }),
@@ -320,7 +327,7 @@ describe('inline document upload (beroep step)', () => {
   });
 
   it('blocks the beroep step until a required category is satisfied', () => {
-    let s = reduce(invullen(validDraft, 1), {
+    let s = reduce(toBeroepStepWithDiploma(), {
       tag: 'Upload',
       msg: { type: 'CategoriesLoaded', categories: [cat] },
     });
@@ -339,7 +346,7 @@ describe('inline document upload (beroep step)', () => {
   });
 
   it('includes delivery refs in the submitted data', () => {
-    let s = reduce(invullen(validDraft), {
+    let s = reduce(toFullDraftAtCursor0(), {
       tag: 'Upload',
       msg: { type: 'CategoriesLoaded', categories: [cat] },
     });

apps/ssp/src/app/registratie/domain/registratie-wizard.testing.ts

@@ -0,0 +1,7 @@
+import { given } from '@shared/testing/machine';
+import { reduce, initial } from './registratie-wizard.machine';
+
+/** Replay real `RegistratieMsg`s through the real `reduce`, starting from
+    `initial`. Pure TS only (no Angular) — domain/ stays framework-free
+    (dependency-cruiser `domain-is-pure`). See `libs/shared/src/testing/machine.ts`. */
+export const givenRegistratieWizard = given(reduce, initial);