Habanero.Faces.Base.StringStaticFilter.GetFilterClause C# (CSharp) Method

        public IFilterClause GetFilterClause(IFilterClauseFactory filterClauseFactory) {
            return string.IsNullOrEmpty(_constantvalue)
                       ? filterClauseFactory.CreateNullFilterClause()
                       : filterClauseFactory.CreateStringFilterClause(_propertyName, _filterClauseOperator, _constantvalue);
        }

 public void Test_GetFilterClause_WhenOpIs_ShouldNotSetValueDelimiters()
 {
     //---------------Set up test pack-------------------
     string propertyName = TestUtil.GetRandomString();
     const FilterClauseOperator filterClauseOperator = FilterClauseOperator.Is;
     const string filterValue = "NULL";
     StringStaticFilter filter = new StringStaticFilter(propertyName, filterClauseOperator, filterValue);
     //---------------Execute Test ----------------------
     IFilterClause filterClause = filter.GetFilterClause(new DataViewFilterClauseFactory());
     //---------------Test Result -----------------------
     Assert.AreEqual(string.Format("{0} Is {1}", propertyName, filterValue), filterClause.GetFilterClauseString()); 
 }