public void ShouldThrowExceptionWhenAddCommentFails()
{
_commentsRepository = new Mock<ICommentRepository>();
_commentsRepository.Setup(a => a.Add(It.IsAny<Comment>())).Throws(new Exception());
_userRepository = new Mock<IUserRepository>();
_commentsLogic = new CommentsLogic(_commentsRepository.Object, _userRepository.Object);
Assert.Throws<BlogException>(() => _commentsLogic.Add(new Common.Contracts.Comment()));
}