test(backend): type-state Aanvraag builder, illegal fixtures unrepresentable (WP-70)

RuleTests/OpenZaakZaakSourceTests hand-built Aanvraag fixtures by initializer,
keeping Submitted/Referentie/SubmittedAt/BesluitStatus consistent by hand. A
type-state builder (Given.Concept().Submitted().Decided()) makes an illegal
sequence a compile error instead, and delegates the toelichting-required rule
to the real BeoordelingRules so it can't drift from production. Adds
BesluitLifecycleTests covering the WP-68 besluit invariants end to end.

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

backend/tests/BigRegister.Tests/Acceptance/BesluitLifecycleTests.cs

@@ -0,0 +1,111 @@
+using System.Net;
+using System.Net.Http.Json;
+using BigRegister.Api.Contracts;
+using BigRegister.Api.Data;
+using BigRegister.Domain.Applications;
+using BigRegister.Domain.Beoordeling;
+using BigRegister.Tests.Builders;
+
+namespace BigRegister.Tests.Acceptance;
+
+/// <summary>
+/// Behaviour-level tests for the besluit lifecycle (WP-65b/66/68), built through the
+/// <see cref="Given"/> type-state builder (WP-70) rather than the full wizard/upload dance
+/// <see cref="BeoordelingTests"/> uses — a fixture that's already Submitted (or already
+/// Decided) is a two-line Given, not fifteen. Each test persists its own Given-built
+/// <see cref="Aanvraag"/> straight into the isolated per-class SQLite file (no HTTP round trip
+/// needed to create it) and exercises the real write path from there.
+/// </summary>
+public class BesluitLifecycleTests(TestWebApplicationFactory factory) : IClassFixture<TestWebApplicationFactory>
+{
+  // Booting the client (once, here) is what makes Db.ConnectionString point at THIS class's
+  // throwaway file and runs its migrations — see TestWebApplicationFactory's own docs.
+  private readonly HttpClient _client = factory.CreateClient();
+
+  private static void Persist(Aanvraag aanvraag)
+  {
+    using var db = Db.Create();
+    db.Applications.Add(aanvraag);
+    db.SaveChanges();
+  }
+
+  [Fact]
+  public void A_terminal_besluit_is_frozen()
+  {
+    // Given a case already decided Goedgekeurd — terminal, per BeoordelingRules.CanDecide.
+    var aanvraag = Given.Concept(type: "registratie").Submitted().Decided(Besluit.Goedkeuren).Build();
+    Persist(aanvraag);
+
+    // When a behandelaar tries to record a further besluit on it...
+    var (outcome, updated) = ApplicationStore.RecordBesluit(aanvraag.Id, Besluit.Afwijzen, "te laat", DateTimeOffset.UtcNow);
+
+    // Then the write is refused, and the original decision still stands.
+    Assert.Equal(ApplicationStore.RecordBesluitOutcome.Conflict, outcome);
+    Assert.Null(updated);
+    var stillGoedgekeurd = ApplicationStore.GetAny(aanvraag.Id)!.StatusAt(DateTimeOffset.UtcNow);
+    Assert.Equal(AanvraagStatusTag.Goedgekeurd, stillGoedgekeurd.Tag);
+  }
+
+  [Fact]
+  public void MeerInfoGevraagd_can_be_decided_again()
+  {
+    // Given a case a behandelaar sent back for more information — not terminal.
+    var aanvraag = Given.Concept(type: "registratie").Submitted().Decided(Besluit.MeerInfoOpvragen, "stuur een geldig diploma").Build();
+    Persist(aanvraag);
+
+    // When a further besluit is recorded on it...
+    var (outcome, updated) = ApplicationStore.RecordBesluit(aanvraag.Id, Besluit.Goedkeuren, null, DateTimeOffset.UtcNow);
+
+    // Then, unlike a terminal decision, it succeeds and advances the status.
+    Assert.Equal(ApplicationStore.RecordBesluitOutcome.Ok, outcome);
+    Assert.Equal(AanvraagStatusTag.Goedgekeurd, updated!.StatusAt(DateTimeOffset.UtcNow).Tag);
+  }
+
+  [Fact]
+  public void A_recorded_decision_wins_over_the_auto_approve_computation()
+  {
+    // Given an auto-approvable submission that a behandelaar decides (Afwijzen) before the
+    // auto-approve window would otherwise have closed it as Goedgekeurd.
+    var aanvraag = Given.Concept(type: "registratie").Submitted(autoApprovable: true).Build();
+    Persist(aanvraag);
+    var (outcome, _) = ApplicationStore.RecordBesluit(aanvraag.Id, Besluit.Afwijzen, "diploma niet erkend", DateTimeOffset.UtcNow);
+    Assert.Equal(ApplicationStore.RecordBesluitOutcome.Ok, outcome);
+
+    // When the status is read long after the auto-approve window has passed — the instant an
+    // undecided auto-approvable case of the same shape WOULD read Goedgekeurd (see
+    // ApplicationTests.AutoApprovable_flips_to_goedgekeurd_after_the_window)...
+    var longAfterTheWindow = aanvraag.SubmittedAt!.Value + ApplicationStore.ProcessingWindow + TimeSpan.FromDays(1);
+    var status = ApplicationStore.GetAny(aanvraag.Id)!.StatusAt(longAfterTheWindow);
+
+    // Then the recorded decision still wins — Afgewezen, never Goedgekeurd.
+    Assert.Equal(AanvraagStatusTag.Afgewezen, status.Tag);
+  }
+
+  private Task<HttpResponseMessage> PostBesluit(string id, object body)
+  {
+    var req = new HttpRequestMessage(HttpMethod.Post, $"/api/v1/beoordeling/{id}/besluit") { Content = JsonContent.Create(body) };
+    req.Headers.Add("X-Medewerker", "medewerker-1");
+    return _client.SendAsync(req);
+  }
+
+  [Fact]
+  public async Task Afwijzen_requires_a_toelichting()
+  {
+    // Given an open, decidable case (no decision recorded yet).
+    var aanvraag = Given.Concept(type: "registratie").Submitted().Build();
+    Persist(aanvraag);
+
+    // When a behandelaar posts Afwijzen with no toelichting...
+    var missing = await PostBesluit(aanvraag.Id, new { besluit = "Afwijzen" });
+
+    // Then the request is rejected — the wire boundary enforces the same rule
+    // (BeoordelingRules.RequiresToelichting) the builder enforces for a built fixture.
+    Assert.Equal(HttpStatusCode.BadRequest, missing.StatusCode);
+
+    // And the identical request WITH a toelichting succeeds.
+    var withToelichting = await PostBesluit(aanvraag.Id, new { besluit = "Afwijzen", toelichting = "Diploma niet erkend" });
+    withToelichting.EnsureSuccessStatusCode();
+    var body = (await withToelichting.Content.ReadFromJsonAsync<RecordBesluitResponse>())!;
+    Assert.Equal("Afgewezen", body.Status.Tag);
+  }
+}