public async void ByExternalId_Not_Exists() { var mock = new ServiceMockFacade <IBucketService, IBucketRepository>(); mock.RepositoryMock.Setup(x => x.ByExternalId(It.IsAny <Guid>())).Returns(Task.FromResult <Bucket>(null)); var service = new BucketService(mock.LoggerMock.Object, mock.MediatorMock.Object, mock.RepositoryMock.Object, mock.ModelValidatorMockFactory.BucketModelValidatorMock.Object, mock.DALMapperMockFactory.DALBucketMapperMock, mock.DALMapperMockFactory.DALFileMapperMock); ApiBucketServerResponseModel response = await service.ByExternalId(default(Guid)); response.Should().BeNull(); mock.RepositoryMock.Verify(x => x.ByExternalId(It.IsAny <Guid>())); }