public void TestIsWithoutValue()
        {
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.Eq));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.Gt));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.GtEq));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.In));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.Like));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.Lt));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.LtEq));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.NotEq));
            Assert.False(_whereAttributeManager.IsWithoutValue(WhereType.NotIn));

            Assert.True(_whereAttributeManager.IsWithoutValue(WhereType.IsNotNull));
            Assert.True(_whereAttributeManager.IsWithoutValue(WhereType.IsNull));
        }