test(bff): relay a refused diploma as 422 with its reason, a down scanner as 503 (refs #192)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

services/bff/Bff.Tests/SelfServiceEndpointTests.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Http.Headers;
 using System.Net.Http.Json;
+using System.Text.Json;
 using Bff.Api;
 
 namespace Bff.Tests;
@@ -162,13 +163,39 @@ public class SelfServiceEndpointTests
     public async Task Relays_not_found_providing_documents_for_an_unknown_or_not_owned_registration()
     {
         using var factory = new BffFactory();
-        factory.Domain.ProvideDocumentsSucceeds = false;
+        factory.Domain.ProvideDocumentsResult = ProvideDocumentsResult.NotFound;
 
         var response = await factory.CreateClient().SendAsync(ProvideDocuments(TestTokens.Valid("123456782")));
 
         Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
     }
 
+    // S-29 (#192): the domain's refusal reaches the portal — 422 with the reason it words for the citizen.
+    [Theory]
+    [InlineData(ProvideDocumentsResult.NotAPdf, "not-a-pdf")]
+    [InlineData(ProvideDocumentsResult.Infected, "infected")]
+    public async Task Relays_a_refused_document_as_unprocessable_with_its_reason(ProvideDocumentsResult result, string reason)
+    {
+        using var factory = new BffFactory();
+        factory.Domain.ProvideDocumentsResult = result;
+
+        var response = await factory.CreateClient().SendAsync(ProvideDocuments(TestTokens.Valid("123456782")));
+
+        Assert.Equal(HttpStatusCode.UnprocessableEntity, response.StatusCode);
+        Assert.Equal(reason, (await response.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("reason").GetString());
+    }
+
+    [Fact]
+    public async Task Relays_an_unavailable_scanner_as_service_unavailable()
+    {
+        using var factory = new BffFactory();
+        factory.Domain.ProvideDocumentsResult = ProvideDocumentsResult.ScannerUnavailable;
+
+        var response = await factory.CreateClient().SendAsync(ProvideDocuments(TestTokens.Valid("123456782")));
+
+        Assert.Equal(HttpStatusCode.ServiceUnavailable, response.StatusCode);
+    }
+
     private static HttpRequestMessage Current(string? bearer)
     {
         var request = new HttpRequestMessage(HttpMethod.Get, "/self-service/registrations");