public async Task GetCourseAsync_CreatesMailingAndReturnsIt() { //arrange var model = new GetMailingModel() { Name = "probability theory" }; //act var mail1 = await _service.GetCourseAsync(1); var mail2 = await _service.GetCourseAsync(model); // assert Assert.IsTrue(_mailingsDb.ContainsValue(mail1)); Assert.IsTrue(_mailingsDb.ContainsKey(mail1.MailingId)); Assert.IsTrue(_mailingsDb.ContainsValue(mail2)); Assert.IsTrue(_mailingsDb.ContainsKey(mail2.MailingId)); }