/// <summary>
        /// A method used to verify the relationship between CHOICES and MAPPINGS elements. If the CHOICES element present, the protocol SUT should provide a MAPPINGS element. Each CHOICE element should found a mapped MAPPING item.
        /// </summary>
        /// <param name="fieldDefinition">A parameter represents the FieldDefinition instance which contains the CHOICES and MAPPINGS elements.</param>
        /// <returns>Return 'true' indicating the relationship validation pass.</returns>
        private bool VerifyChoicesAndMappingsRelationShip(FieldDefinition fieldDefinition)
        {
           if (null == fieldDefinition.MAPPINGS)
           {
               throw new ArgumentException("The fieldDfinition should contain valid MAPPINGDEFINITION[] type instance.", string.Empty);
           }

           if (null == fieldDefinition.CHOICES)
           {
               throw new ArgumentException("The fieldDfinition should contain valid MAPPINGDEFINITION[] type instance.");
           }

           if (0 == fieldDefinition.MAPPINGS.Length || 0 == fieldDefinition.CHOICES.Length)
           {
               // If the MAPPINGS and CHOICES element does not contain any item, it is match the TD.
               return true;
           }

           if (fieldDefinition.MAPPINGS.Length != fieldDefinition.CHOICES.Length)
           {
               this.Site.Assert.Fail("The MAPPING items' number should equal to the CHOICE items' number.");
           }

           bool isMappingItemsMatchChoicesItems = false;
           foreach (CHOICEDEFINITION choiceItem in fieldDefinition.CHOICES)
           {
               string choiceItemValue = choiceItem.Text[0];

               // The choice item Value should be found in MAPPINGS array.
               isMappingItemsMatchChoicesItems = fieldDefinition.MAPPINGS.Any(Founder => Founder.Value1.Equals(choiceItemValue, StringComparison.OrdinalIgnoreCase));
               if (!isMappingItemsMatchChoicesItems)
               {
                   break;
               }
           }

           return isMappingItemsMatchChoicesItems;
        }