public void FilterByAdditionalFilters_SkipsNullValues()
        {
            datalist.Filter.AdditionalFilters.Add("Id", null);

            IQueryable <TestModel> actual   = datalist.FilterByAdditionalFilters(datalist.GetModels());
            IQueryable <TestModel> expected = datalist.GetModels();

            Assert.Equal(expected, actual);
        }