feat: добавил поддержку подписки на календарь и экспорт расписания лекций в формате .ics

backend/UniVerse.Api.Tests/Users/UserServiceTests.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
 using UniVerse.Application.DTOs.Notifications;
@@ -193,6 +194,56 @@ public class UserServiceTests
         Assert.Equal(2, Assert.Single(result.Items).Id);
     }
 
+    [Fact]
+    public async Task CalendarSubscriptionToken_Roundtrip_ReturnsUserEnrollmentsIcs()
+    {
+        await using var db = CreateDbContext();
+        var startsAt = new DateTime(2026, 1, 10, 9, 0, 0, DateTimeKind.Utc);
+        db.Users.Add(new User { Id = 1, Email = "student@test.local" });
+        db.Courses.Add(new Course { Id = 1, Name = "Course" });
+        db.Lectures.Add(Lecture(1, startsAt));
+        db.LectureEnrollments.Add(new LectureEnrollment { LectureId = 1, UserId = 1 });
+        await db.SaveChangesAsync();
+        var service = CreateService(db);
+
+        var token = await service.GetCalendarSubscriptionTokenAsync(1);
+        var ics = await service.GetEnrollmentsIcsBySubscriptionTokenAsync(token);
+
+        Assert.Contains("BEGIN:VCALENDAR", ics);
+        Assert.Contains("Lecture 1", ics);
+    }
+
+    [Fact]
+    public async Task CalendarSubscriptionToken_RejectsTamperedToken()
+    {
+        await using var db = CreateDbContext();
+        db.Users.Add(new User { Id = 1, Email = "student@test.local" });
+        await db.SaveChangesAsync();
+        var service = CreateService(db);
+        var token = await service.GetCalendarSubscriptionTokenAsync(1);
+        var tampered = token[..^1] + (token[^1] == 'A' ? 'B' : 'A');
+
+        await Assert.ThrowsAsync<ForbiddenException>(() =>
+            service.GetEnrollmentsIcsBySubscriptionTokenAsync(tampered));
+    }
+
+    [Fact]
+    public async Task GetEnrollmentIcsAsync_ReturnsLectureIcsWithoutEnrollment()
+    {
+        await using var db = CreateDbContext();
+        var startsAt = new DateTime(2026, 2, 10, 9, 0, 0, DateTimeKind.Utc);
+        db.Users.Add(new User { Id = 1, Email = "student@test.local" });
+        db.Courses.Add(new Course { Id = 1, Name = "Course" });
+        db.Lectures.Add(Lecture(1853, startsAt));
+        await db.SaveChangesAsync();
+        var service = CreateService(db);
+
+        var ics = await service.GetEnrollmentIcsAsync(1, 1853);
+
+        Assert.Contains("BEGIN:VCALENDAR", ics);
+        Assert.Contains("Lecture 1853", ics);
+    }
+
     private static AppDbContext CreateDbContext()
     {
         var options = new DbContextOptionsBuilder<AppDbContext>()
@@ -215,7 +266,13 @@ public class UserServiceTests
             .Returns(Task.CompletedTask);
 
         var gamification = new GamificationService(db, notifications, NullLogger<GamificationService>.Instance);
-        return new UserService(db, gamification);
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["Jwt:Secret"] = "test-calendar-subscription-secret-32chars"
+            })
+            .Build();
+        return new UserService(db, gamification, config);
     }
 
     private static void SeedLevelThresholds(AppDbContext db)