public void Details_with_article_id_should_return_article()
{
var article = new Article();
//given
_repository.Setup(x => x.Get(It.IsAny <Guid>()))
.Returns(article);
//when
var result = _controller.Details(Guid.NewGuid()) as ViewResult;
//then
result.ViewData.Model.Should().BeSameAs(article);
}