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>()));
}