public async Task CallFilterSpellsAsync_WhenCalled()
        {
            // Arrange
            Mock <ISpellService> spellServiceMock = new Mock <ISpellService>();
            Mock <IPDFService>   pDFServiceMock   = new Mock <IPDFService>();
            Mock <IMemoryCache>  memoryCacheMock  = new Mock <IMemoryCache>();

            string validSortOrder  = string.Empty;
            string validFilter     = string.Empty;
            int    validPageNumber = 1;
            int    validPageSize   = 10;

            IPagedList <Spell> spells = new PagedList <Spell>(new List <Spell>().AsQueryable(), validPageNumber, validPageSize);

            spellServiceMock.Setup(mock => mock.FilterSpellsAsync(validSortOrder, validFilter, validPageNumber, validPageSize))
            .Returns(Task.FromResult(spells));

            SpellController SUT = new SpellController(
                spellServiceMock.Object,
                pDFServiceMock.Object,
                memoryCacheMock.Object);

            // Act
            await SUT.Filter(validSortOrder, validFilter, validPageNumber, validPageSize);

            // Assert
            spellServiceMock
            .Verify(mock => mock.FilterSpellsAsync(validSortOrder, validFilter, validPageNumber, validPageSize),
                    Times.Once);
        }
        public async Task ReturnCorrectViewModel_WhenCalled()
        {
            // Arrange
            Mock <ISpellService> spellServiceMock = new Mock <ISpellService>();
            Mock <IPDFService>   pDFServiceMock   = new Mock <IPDFService>();
            Mock <IMemoryCache>  memoryCacheMock  = new Mock <IMemoryCache>();

            string validSortOrder  = string.Empty;
            string validFilter     = string.Empty;
            int    validPageNumber = 1;
            int    validPageSize   = 10;

            IPagedList <Spell> spells = new PagedList <Spell>(new List <Spell>().AsQueryable(), validPageNumber, validPageSize);

            spellServiceMock.Setup(mock => mock.FilterSpellsAsync(validSortOrder, validFilter, validPageNumber, validPageSize))
            .Returns(Task.FromResult(spells));

            SpellController SUT = new SpellController(
                spellServiceMock.Object,
                pDFServiceMock.Object,
                memoryCacheMock.Object);

            // Act
            var result = await SUT.Filter(validSortOrder, validFilter, validPageNumber, validPageSize) as PartialViewResult;

            // Assert
            Assert.IsInstanceOfType(result.Model, typeof(TableViewModel <SpellViewModel>));
        }