public async void ByExternalId_Not_Exists()
{
var mock = new ServiceMockFacade <ILinkService, ILinkRepository>();
mock.RepositoryMock.Setup(x => x.ByExternalId(It.IsAny <Guid>())).Returns(Task.FromResult <Link>(null));
var service = new LinkService(mock.LoggerMock.Object,
mock.MediatorMock.Object,
mock.RepositoryMock.Object,
mock.ModelValidatorMockFactory.LinkModelValidatorMock.Object,
mock.DALMapperMockFactory.DALLinkMapperMock,
mock.DALMapperMockFactory.DALLinkLogMapperMock);
ApiLinkServerResponseModel response = await service.ByExternalId(default(Guid));
response.Should().BeNull();
mock.RepositoryMock.Verify(x => x.ByExternalId(It.IsAny <Guid>()));
}
