public async Task ListAsyncWhenNoSessionDetailsReturnsEmptyCollection() { var mockSessionDetailRepository = GetDefaultISessionDetailRepositoryInstance(); mockSessionDetailRepository.Setup(r => r.ListAsync()) .ReturnsAsync(new List <SessionDetail>()); var mockUnitOfWork = GetDefaultIUnitOfWorkInstance(); var service = new SessionDetailService( mockSessionDetailRepository.Object, mockUnitOfWork.Object); // Act List <SessionDetail> result = (List <SessionDetail>) await service.ListAsync(); int sessionDetailssCount = result.Count; // Assert sessionDetailssCount.Should().Equals(0); }