atomic-design-poc/backend/tests/BigRegister.Tests/OpenZaakZaakSourceTests.cs

using System.Net;
using System.Text;
using BigRegister.Api.Zgw;

namespace BigRegister.Tests;

/// <summary>
/// Exercises the OpenZaak read source against a stub HttpMessageHandler (no live server, no
/// mocking library) — the guarantee that it follows ZGW pagination, resolves + caches
/// zaaktype labels, and always sends a Bearer token.
/// </summary>
public class OpenZaakZaakSourceTests
{
  private const string ZrcBase = "https://oz.example/zaken/api/v1";
  private const string ZtBase = "https://oz.example/catalogi/api/v1";

  private static string Page1 => $$"""
    { "count": 2, "next": "{{ZrcBase}}/zaken?page=2", "results": [
      { "url": "{{ZrcBase}}/zaken/uuid-1", "identificatie": "ZAAK-1",
        "zaaktype": "{{ZtBase}}/zaaktypen/zt-1", "startdatum": "2026-03-01",
        "einddatum": null, "registratiedatum": "2026-03-01" } ] }
    """;

  private static string Page2 => $$"""
    { "count": 2, "next": null, "results": [
      { "url": "{{ZrcBase}}/zaken/uuid-2", "identificatie": "ZAAK-2",
        "zaaktype": "{{ZtBase}}/zaaktypen/zt-1", "startdatum": "2026-01-01",
        "einddatum": "2026-02-01", "registratiedatum": "2026-01-01" } ] }
    """;

  private const string Zaaktype = """{ "omschrijving": "Herregistratie arts" }""";

  [Fact]
  public void Follows_pagination_caches_zaaktype_and_sends_bearer_token()
  {
    var handler = new StubHandler(url => url switch
    {
      _ when url == $"{ZrcBase}/zaken" => Page1,
      _ when url == $"{ZrcBase}/zaken?page=2" => Page2,
      _ when url == $"{ZtBase}/zaaktypen/zt-1" => Zaaktype,
      _ => throw new InvalidOperationException($"unexpected ZGW GET {url}"),
    });

    var options = new ZgwOptions { ZrcBaseUrl = ZrcBase, ZtcBaseUrl = ZtBase, ClientId = "c", Secret = "s" };
    var source = new OpenZaakZaakSource(new HttpClient(handler), new ZgwTokenProvider(options), options);

    var cases = source.ListCases(DateTimeOffset.UtcNow);

    // Both pages accumulated.
    Assert.Equal(2, cases.Count);
    Assert.Equal(new[] { "uuid-1", "uuid-2" }, cases.Select(c => c.Id));
    Assert.All(cases, c => Assert.Equal("Herregistratie arts", c.Type));
    Assert.Equal("InBehandeling", cases[0].Status.Tag);   // open
    Assert.Equal("Goedgekeurd", cases[1].Status.Tag);     // closed

    // Zaaktype resolved once despite two zaken sharing it (cache).
    Assert.Single(handler.Requests, r => r.Contains("zaaktypen"));
    // Every outbound request carried a Bearer token.
    Assert.All(handler.AuthSchemes, s => Assert.Equal("Bearer", s));
  }

  private sealed class StubHandler(Func<string, string> respond) : HttpMessageHandler
  {
    public List<string> Requests { get; } = new();
    public List<string?> AuthSchemes { get; } = new();

    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
      var url = request.RequestUri!.ToString();
      Requests.Add(url);
      AuthSchemes.Add(request.Headers.Authorization?.Scheme);
      return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
      {
        Content = new StringContent(respond(url), Encoding.UTF8, "application/json"),
      });
    }
  }
}