public void AddPages_returns_success_result_if_pages_are_empty()
        {
            //arrange
            Mock <IPageRepository> pageRepo = new Mock <IPageRepository>();
            Mock <IUnitOfWork>     uow      = new Mock <IUnitOfWork>();

            pageRepo.Setup(rep => rep.AddRange(null)).Throws <ArgumentNullException>();
            pageRepo.Setup(rep => rep.AddRange(It.IsNotNull <IEnumerable <Page> >()));
            uow.Setup(u => u.PageRepository).Returns(pageRepo.Object);
            TestManager manager = new TestManager(uow.Object);
            //act
            var emptyPagesAdd = manager.AddPages(new Page[] { }).Result;

            //assert
            Assert.True(emptyPagesAdd.Succeeded);
        }
        public void AddPages_returns_success_result_if_pages_are_not_empty()
        {
            //arrange
            Mock <IPageRepository> pageRepo = new Mock <IPageRepository>();
            Mock <IUnitOfWork>     uow      = new Mock <IUnitOfWork>();

            pageRepo.Setup(rep => rep.AddRange(It.IsNotNull <IEnumerable <Page> >()))
            .Callback <IEnumerable <Page> >(pages => _pages.AddRange(pages));

            uow.Setup(u => u.PageRepository).Returns(pageRepo.Object);

            TestManager manager = new TestManager(uow.Object);

            var oldCount = _pages.Count;
            //act

            var emptyPagesAdd = manager.AddPages(_addPages).Result;

            //assert
            Assert.True(emptyPagesAdd.Succeeded);
            Assert.Equal(_pages.Count, oldCount + _addPages.Count);
            Assert.True(_pages.Any(p => _addPages.Contains(p)));
            pageRepo.Verify(p => p.AddRange(It.IsNotNull <IEnumerable <Page> >()));
        }