test: split multi-assertion specs into single-behavior tests

One behavior per test across FE machine/store specs and backend endpoint
tests, so a failure names exactly what broke.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/registratie/domain/change-request.machine.spec.ts

@@ -34,15 +34,27 @@ describe('change-request reduce', () => {
     expect((s as Extract<ChangeRequestState, { tag: 'Submitting' }>).data.postcode).toBe('2514 EA');
   });
 
-  it('confirms and fails only from Submitting; Retry re-submits a failure', () => {
+  it('SubmitConfirmed maps Submitting to Submitted with the referentie', () => {
     const submitting = reduce(editingWith({ straat: 'A 1', postcode: '2514 EA' }), {
       tag: 'Submit',
     });
     const ok = reduce(submitting, { tag: 'SubmitConfirmed', referentie: 'BIG-2026-1' });
     expect(ok).toMatchObject({ tag: 'Submitted', referentie: 'BIG-2026-1' });
+  });
 
+  it('SubmitFailed maps Submitting to Failed with the error', () => {
+    const submitting = reduce(editingWith({ straat: 'A 1', postcode: '2514 EA' }), {
+      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({ straat: 'A 1', postcode: '2514 EA' }), {
+      tag: 'Submit',
+    });
+    const failed = reduce(submitting, { tag: 'SubmitFailed', error: 'boom' });
     expect(reduce(failed, { tag: 'Retry' }).tag).toBe('Submitting');
   });
 

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

@@ -187,8 +187,11 @@ describe('manual diploma fallback', () => {
 });
 
 describe('submit', () => {
-  it('reaches Indienen ONLY with a complete, valid draft', () => {
-    expect(submit(invullen(validAdres)).tag).toBe('Invullen'); // no diploma
+  it('stays in Invullen when the draft is incomplete (no diploma)', () => {
+    expect(submit(invullen(validAdres)).tag).toBe('Invullen');
+  });
+
+  it('reaches Indienen with a complete, valid draft, carrying its data', () => {
     const good = submit(invullen(validDraft));
     expect(good.tag).toBe('Indienen');
     expect((good as any).data.beroep).toBe('Arts');
@@ -196,11 +199,14 @@ describe('submit', () => {
     expect((good as any).data.adresHerkomst).toBe('brp');
   });
 
-  it('resolve maps Indienen to Ingediend (with referentie) / Mislukt', () => {
-    const indienen = submit(invullen(validDraft));
-    expect(resolve(indienen, ok('BIG-2026-001')).tag).toBe('Ingediend');
-    expect((resolve(indienen, ok('BIG-2026-001')) as any).referentie).toBe('BIG-2026-001');
-    expect(resolve(indienen, err('boom')).tag).toBe('Mislukt');
+  it('resolve maps Indienen to Ingediend with the referentie', () => {
+    const ingediend = resolve(submit(invullen(validDraft)), ok('BIG-2026-001'));
+    expect(ingediend.tag).toBe('Ingediend');
+    expect((ingediend as any).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');
   });
 });
 
@@ -225,13 +231,20 @@ describe('reduce (message-driven happy path)', () => {
     expect(s.tag).toBe('Ingediend');
   });
 
-  it('SubmitFailed then Retry returns to Indienen with the same data', () => {
-    let s = reduce(reduce(invullen(validDraft), { tag: 'Submit' }), {
+  it('SubmitFailed moves Indienen to Mislukt', () => {
+    const s = reduce(reduce(invullen(validDraft), { tag: 'Submit' }), {
       tag: 'SubmitFailed',
       error: 'boom',
     });
     expect(s.tag).toBe('Mislukt');
-    s = reduce(s, { tag: 'Retry' });
+  });
+
+  it('Retry returns Mislukt to Indienen with the same data', () => {
+    const mislukt = reduce(reduce(invullen(validDraft), { tag: 'Submit' }), {
+      tag: 'SubmitFailed',
+      error: 'boom',
+    });
+    const s = reduce(mislukt, { tag: 'Retry' });
     expect(s.tag).toBe('Indienen');
     expect((s as any).data.beroep).toBe('Arts');
   });