public void TestConstructor()
        {
            //empty dataElement
            ConditionDisplayParameterCustomPropertyValue customPropertyValueParam = new ConditionDisplayParameterCustomPropertyValue(CustomPropertyType.Text, null, this.Callback, Workshare.Policy.PolicyType.ClientEmail);
            Assert.IsTrue(Object.ReferenceEquals(null, customPropertyValueParam.Object), "unexpected Object");
            Assert.AreEqual(Properties.Resources.IDS_EXPRESSION_PARAM_CUSTOMPROPERTYVALUE_DEFAULT, customPropertyValueParam.Text, "unexpected Text");
            Assert.AreEqual(Enum.GetName(typeof(CustomPropertyType), CustomPropertyType.Text), customPropertyValueParam.Type.ToString(), "unexpected custom property type");

            //nominal case with no display name
            IDataElement dataElement = new DataElement(Guid.NewGuid(), new NonTranslateableLanguageItem("name"), new NonTranslateableLanguageItem(""), DataType.String, DataItem.CreateDataItem(new NonTranslateableLanguageItem(""), DataType.String, "My Doc Type"));
            customPropertyValueParam = new ConditionDisplayParameterCustomPropertyValue(CustomPropertyType.Text, dataElement, this.Callback, Workshare.Policy.PolicyType.ClientEmail);
            Assert.IsTrue(Object.ReferenceEquals(dataElement, customPropertyValueParam.Object), "unexpected Object");
            Assert.AreEqual("My Doc Type", customPropertyValueParam.Text, "unexpected Text");
            Assert.AreEqual(Enum.GetName(typeof(CustomPropertyType), CustomPropertyType.Text), customPropertyValueParam.Type.ToString(), "unexpected custom property type");

            m_callbackCalled = false;
            customPropertyValueParam.Execute();
            Assert.IsTrue(m_callbackCalled, "Execute not called");

            //nominal case with display name
            dataElement.DisplayName.Value = "This is a display name";
            customPropertyValueParam = new ConditionDisplayParameterCustomPropertyValue(CustomPropertyType.Text, dataElement, this.Callback, Workshare.Policy.PolicyType.ClientEmail);
            Assert.IsTrue(Object.ReferenceEquals(dataElement, customPropertyValueParam.Object), "unexpected Object");
            Assert.AreEqual("My Doc Type", customPropertyValueParam.Text, "unexpected Text - display name should be the same as dataElement");
            Assert.AreEqual(Enum.GetName(typeof(CustomPropertyType), CustomPropertyType.Text), customPropertyValueParam.Type.ToString(), "unexpected custom property type");

            m_callbackCalled = false;
            customPropertyValueParam.Execute();
            Assert.IsTrue(m_callbackCalled, "Execute not called");

            //invalid format case
            try
            {
                dataElement = new DataElement(Guid.NewGuid(), new NonTranslateableLanguageItem("name"), new NonTranslateableLanguageItem(""), DataType.StringArray, new PolicyObjectCollection<IDataItem>());
                customPropertyValueParam = new ConditionDisplayParameterCustomPropertyValue(CustomPropertyType.Text, dataElement, this.Callback, Workshare.Policy.PolicyType.ClientEmail);
                Assert.IsTrue(false, "Didnt throw on invalid dataelement");
            }
            catch (PolicyDesignerException)
            {
                Assert.IsTrue(true);
            }
            catch
            {
                Assert.IsTrue(false, "unexpected exception thrown");
            }
        }