public async Task GetByThreadId_ReturnsPost_WhenProvidedValidThreadId() { // Arrange ForumThread thread = new ForumThread { Title = "123", ForumPosts = new List <ForumPost> { new ForumPost { Content = "test" } } }; DbContext.Threads.Add(thread); await DbContext.SaveChangesAsync(); // Act IReadOnlyCollection <ForumPost> posts = await _postsRepository.GetByThread(thread.Id); // Assert Assert.That(posts, Has.Count.EqualTo(1)); }