public async Task TestGetCategoriesByProgramIdAsync()
        {
            var response = await controller.GetCategoriesByProgramIdAsync(1, new PagingQueryBindingModel <FocusCategoryDTO>());

            Assert.IsInstanceOfType(response, typeof(OkNegotiatedContentResult <PagedQueryResults <FocusCategoryDTO> >));
            focusCategoryService.Verify(x => x.GetFocusCategoriesByProgramIdAsync(It.IsAny <int>(), It.IsAny <QueryableOperator <FocusCategoryDTO> >()), Times.Once());
        }