public async Task GetByIdAsyncWhenNoStartupFoundReturnsStartupNotFoundResponse() { // Arrange var mockStartupRepository = GetDefaultIStartupRepositoryInstance(); var mockUnitOfWork = GetDefaultIUnitOfWorkInstance(); var startupId = 1; mockStartupRepository.Setup(r => r.FindById(startupId)) .Returns(Task.FromResult <Domain.Models.Startup>(null)); var service = new StartupService(mockStartupRepository.Object, mockUnitOfWork.Object); // Act StartupResponse result = await service.GetByIdAsync(startupId); var message = result.Message; // Assert message.Should().Be("Startup not found"); }