public void ShouldThrowExceptionWhenGetCommentsByPostFails()
{
_commentsRepository = new Mock<ICommentRepository>();
_commentsRepository.Setup(a => a.Find(It.IsAny<Expression<Func<Comment, bool>>>(),
It.IsAny<Func<IQueryable<Comment>, IOrderedQueryable<Comment>>>(), It.IsAny<string>()))
.Throws(new Exception());
_userRepository = new Mock<IUserRepository>();
_commentsLogic = new CommentsLogic(_commentsRepository.Object, _userRepository.Object);
Assert.Throws<BlogException>(() => _commentsLogic.GetByPostId(1));
}