Baustein 8: Settings-Tab "Synchronisation" (Kapitel 10)

Neuer Tab in den Einstellungen: Server-URL, Login, Verbindungstest,
Logout.

- Neu SyncSettingsService (Muster AiSettingsService): Token
  AES-256-verschluesselt ueber SyncCrypto mit eigenem, rein lokalem
  Schluessel - ersetzt die bisherigen Klartext-Helfer
  AppBootstrapper.LoadServerUrl/SaveServerUrl und die unverschluesselte
  auth.token-Datei
- Neu SyncAuthService fuer den Login-HTTP-Aufruf gegen /api/auth/login
  und den Verbindungstest (unterscheidet erreichbar & angemeldet /
  erreichbar aber nicht angemeldet / nicht erreichbar)
- Speichern/Anmelden startet die App neu (AppBootstrapper.
  RestartApplication, gleiches Muster wie bei DB-Passwort/AppLock-
  Aenderungen) - SyncEngine/SnapshotService werden nur einmalig beim
  Start registriert, es gibt keinen Live-Re-Registrierungspfad

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

LehrerApp.Desktop.Tests/Fakes.cs

@@ -26,6 +26,18 @@ public static class TestSupport
     public static AiPlanningService BuildAiPlanningService() => new(
         new HttpClient(), new FakeLessons(), new FakeGroups([]), new FakeSubjects([]),
         new FakeCompetencyDomains(), new FakeAlternativeLessonPaths([]));
+
+    /// Analog zu <see cref="BuildAiSettingsService"/>, eigenes Temp-Verzeichnis je Aufruf.
+    public static SyncSettingsService BuildSyncSettingsService()
+    {
+        var tempPath = Path.Combine(Path.GetTempPath(), $"lehrerapp-syncsettings-tests-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(tempPath);
+        return new SyncSettingsService(tempPath);
+    }
+
+    /// Kein echter HTTP-Aufruf, solange SyncSettingsService.IsLoggedIn false ist (siehe
+    /// BuildAiPlanningService).
+    public static SyncAuthService BuildSyncAuthService() => new(new HttpClient());
 }
 
 public class FakeStudents(List<Student> all) : IStudentRepository

LehrerApp.Desktop.Tests/SettingsViewModelTests.cs

@@ -26,7 +26,8 @@ public sealed class SettingsViewModelTests
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             holidays ?? new FakeSchoolHolidays(), new SchoolCalendarSettingsService(tempPath),
             new PeriodScheduleService(tempPath), supervisionDuties ?? new FakeSupervisionDuties(),
-            new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService());
+            new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService());
     }
 
     [Fact]
@@ -102,7 +103,8 @@ public sealed class SettingsViewModelTests
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             new FakeSchoolHolidays(), calendarSettings, new PeriodScheduleService(tempPath),
-            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService());
+            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService());
 
         vm.SelectedStateName = "Bayern";
 
@@ -124,7 +126,8 @@ public sealed class SettingsViewModelTests
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             new FakeSchoolHolidays(), new SchoolCalendarSettingsService(tempPath), periodSchedule,
-            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService());
+            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService());
 
         vm.PeriodTimes[0].StartText = "08:00";
         vm.PeriodTimes[0].EndText = "08:45";
@@ -150,7 +153,8 @@ public sealed class SettingsViewModelTests
             new LiteDbContext(new MemoryStream()), new PrivacySettingsService(tempPath),
             new FakeDocumentation(), new FakeStudents([]), new FakeShorthandCodes([]),
             new FakeSchoolHolidays(), new SchoolCalendarSettingsService(tempPath), periodSchedule,
-            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService());
+            new FakeSupervisionDuties(), new LetterTemplateService(tempPath), TestSupport.BuildAiSettingsService(), TestSupport.BuildAiPlanningService(),
+            TestSupport.BuildSyncSettingsService(), TestSupport.BuildSyncAuthService());
 
         vm.PeriodTimes[0].StartText = "08:45";
         vm.PeriodTimes[0].EndText = "08:00";

LehrerApp.Desktop.Tests/SyncSettingsServiceTests.cs

@@ -0,0 +1,76 @@
+using LehrerApp.Desktop.Services;
+using Xunit;
+
+namespace LehrerApp.Desktop.Tests;
+
+public sealed class SyncSettingsServiceTests
+{
+    private static string BuildTempPath()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"lehrerapp-syncsettingssvc-tests-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(path);
+        return path;
+    }
+
+    [Fact]
+    public void SetServerUrl_PersistiertUeberNeueInstanz()
+    {
+        var path = BuildTempPath();
+        new SyncSettingsService(path).SetServerUrl("https://sync.example.com");
+
+        var reloaded = new SyncSettingsService(path);
+
+        Assert.Equal("https://sync.example.com", reloaded.ServerUrl);
+    }
+
+    [Fact]
+    public void SetCredentialsAndToken_TokenIstVerschluesseltAbrufbar()
+    {
+        var service = new SyncSettingsService(BuildTempPath());
+
+        service.SetCredentialsAndToken("sebastian", "geheimes-token-123");
+
+        Assert.True(service.IsLoggedIn);
+        Assert.Equal("sebastian", service.Username);
+        Assert.Equal("geheimes-token-123", service.GetToken());
+    }
+
+    [Fact]
+    public void Token_UeberlebtNeueInstanzMitDemselbenPfad()
+    {
+        var path = BuildTempPath();
+        new SyncSettingsService(path).SetCredentialsAndToken("sebastian", "token-abc");
+
+        var reloaded = new SyncSettingsService(path);
+
+        Assert.True(reloaded.IsLoggedIn);
+        Assert.Equal("token-abc", reloaded.GetToken());
+    }
+
+    [Fact]
+    public void TokenDateiEnthaeltNichtDenKlartext()
+    {
+        var path = BuildTempPath();
+        var service = new SyncSettingsService(path);
+        service.SetCredentialsAndToken("sebastian", "geheimes-token-123");
+
+        var raw = File.ReadAllText(Path.Combine(path, "sync-settings.json"));
+
+        Assert.DoesNotContain("geheimes-token-123", raw);
+    }
+
+    [Fact]
+    public void Logout_EntferntTokenBehaeltAberServerUrlUndUsername()
+    {
+        var service = new SyncSettingsService(BuildTempPath());
+        service.SetServerUrl("https://sync.example.com");
+        service.SetCredentialsAndToken("sebastian", "token-abc");
+
+        service.Logout();
+
+        Assert.False(service.IsLoggedIn);
+        Assert.Null(service.GetToken());
+        Assert.Equal("https://sync.example.com", service.ServerUrl);
+        Assert.Equal("sebastian", service.Username);
+    }
+}