/// <summary>
        /// Validates a <see cref="CountQueryOption" />.
        /// </summary>
        /// <param name="countQueryOption">The $count query.</param>
        /// <param name="validationSettings">The validation settings.</param>
        public virtual void Validate(CountQueryOption countQueryOption, ODataValidationSettings validationSettings)
        {
            if (countQueryOption == null)
            {
                throw Error.ArgumentNull("countQueryOption");
            }

            if (validationSettings == null)
            {
                throw Error.ArgumentNull("validationSettings");
            }

            ODataPath path = countQueryOption.Context.Path;

            if (path != null && path.Segments.Count > 0)
            {
                ODataPathSegment lastSegment = path.Segments.Last();

                if (lastSegment is CountPathSegment && path.Segments.Count > 1)
                {
                    ValidateCount(path.Segments[path.Segments.Count - 2], countQueryOption.Context.Model);
                }
                else
                {
                    ValidateCount(lastSegment, countQueryOption.Context.Model);
                }
            }
        }

        /// <summary>
        /// Validates a <see cref="TopQueryOption" />.
        /// </summary>
        /// <param name="selectExpandQueryOption">The $select and $expand query.</param>
        /// <param name="validationSettings">The validation settings.</param>
        public virtual void Validate(SelectExpandQueryOption selectExpandQueryOption, ODataValidationSettings validationSettings)
        {
            if (selectExpandQueryOption == null)
            {
                throw Error.ArgumentNull("selectExpandQueryOption");
            }

            if (validationSettings == null)
            {
                throw Error.ArgumentNull("validationSettings");
            }

            IEdmModel model = selectExpandQueryOption.Context.Model;
            ValidateRestrictions(selectExpandQueryOption.SelectExpandClause, model);

            if (validationSettings.MaxExpansionDepth > 0)
            {
                if (selectExpandQueryOption.LevelsMaxLiteralExpansionDepth > validationSettings.MaxExpansionDepth)
                {
                    throw new ODataException(Error.Format(
                        SRResources.InvalidExpansionDepthValue,
                        "LevelsMaxLiteralExpansionDepth",
                        "MaxExpansionDepth"));
                }

                ValidateDepth(selectExpandQueryOption.SelectExpandClause, validationSettings.MaxExpansionDepth);
            }
        }

        /// <summary>
        /// Override this method to restrict the 'all' query inside the filter query.
        /// </summary>
        /// <remarks>
        /// This method is intended to be called from method overrides in subclasses. This method also supports unit-testing scenarios and is not intended to be called from user code.
        /// Call the Validate method to validate a <see cref="FilterQueryOption"/> instance.
        /// </remarks>
        /// <param name="allNode"></param>
        /// <param name="settings"></param>
        public virtual void ValidateAllNode(AllNode allNode, ODataValidationSettings settings)
        {
            if (allNode == null)
            {
                throw Error.ArgumentNull("allNode");
            }

            if (settings == null)
            {
                throw Error.ArgumentNull("settings");
            }

            EnterLambda(settings);

            try
            {
                ValidateQueryNode(allNode.Source, settings);

                ValidateQueryNode(allNode.Body, settings);
            }
            finally
            {
                ExitLambda();
            }
        }

        public virtual void Validate(OrderByQueryOption orderByOption, ODataValidationSettings validationSettings)
        {
            if (orderByOption == null)
            {
                throw Error.ArgumentNull("orderByOption");
            }

            if (validationSettings == null)
            {
                throw Error.ArgumentNull("validationSettings");
            }

            if (validationSettings.AllowedOrderByProperties.Count > 0)
            {
                ICollection<OrderByPropertyNode> propertyNodes = orderByOption.PropertyNodes;

                foreach (OrderByPropertyNode property in propertyNodes)
                {
                    if (!validationSettings.AllowedOrderByProperties.Contains(property.Property.Name))
                    {
                        throw new ODataException(Error.Format(SRResources.NotAllowedOrderByProperty, property.Property.Name, "AllowedOrderByProperties"));
                    }
                }
            }
        }

        /// <summary>
        /// Validates the specified query options.
        /// </summary>
        /// <param name="queryOptions">The query options.</param>
        /// <param name="validationSettings">The validation settings.</param>
        /// <exception cref="ODataException">Thrown if the validation fails.</exception>
        internal static void Validate(ODataQueryOptions queryOptions, ODataValidationSettings validationSettings)
        {
            if (queryOptions.Filter != null)
            {
                if ((validationSettings.AllowedQueryOptions & AllowedQueryOptions.Filter) != AllowedQueryOptions.Filter)
                {
                    throw new ODataException(Messages.FilterQueryOptionNotSupported);
                }

                ValidateFunctions(queryOptions.Filter.RawValue, validationSettings);
                ValidateStringFunctions(queryOptions.Filter.RawValue, validationSettings);
                ValidateDateFunctions(queryOptions.Filter.RawValue, validationSettings);
                ValidateMathFunctions(queryOptions.Filter.RawValue, validationSettings);
                ValidateLogicalOperators(queryOptions.Filter.RawValue, validationSettings);
                ValidateArithmeticOperators(queryOptions.Filter.RawValue, validationSettings);
            }

            if (queryOptions.RawValues.Expand != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.Expand) != AllowedQueryOptions.Expand)
            {
                throw new ODataException(Messages.ExpandQueryOptionNotSupported);
            }

            if (queryOptions.RawValues.Format != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.Format) != AllowedQueryOptions.Format)
            {
                throw new ODataException(Messages.FormatQueryOptionNotSupported);
            }

            if (queryOptions.RawValues.InlineCount != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.InlineCount) != AllowedQueryOptions.InlineCount)
            {
                throw new ODataException(Messages.InlineCountQueryOptionNotSupported);
            }

            if (queryOptions.RawValues.OrderBy != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.OrderBy) != AllowedQueryOptions.OrderBy)
            {
                throw new ODataException(Messages.OrderByQueryOptionNotSupported);
            }

            if (queryOptions.RawValues.Select != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.Select) != AllowedQueryOptions.Select)
            {
                throw new ODataException(Messages.SelectQueryOptionNotSupported);
            }

            if (queryOptions.RawValues.Skip != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.Skip) != AllowedQueryOptions.Skip)
            {
                throw new ODataException(Messages.SkipQueryOptionNotSupported);
            }

            if (queryOptions.RawValues.Top != null
                && (validationSettings.AllowedQueryOptions & AllowedQueryOptions.Top) != AllowedQueryOptions.Top)
            {
                throw new ODataException(Messages.TopQueryOptionNotSupported);
            }
        }

        public void Validate_NoException_ForAllowedAndSortableUnlimitedProperty_OnEmptyAllowedPropertiesList()
        {
            // Arrange: empty allowed orderby list
            ODataValidationSettings settings = new ODataValidationSettings();

            // Act & Assert
            Assert.DoesNotThrow(() => _validator.Validate(new OrderByQueryOption("Name asc", _context), settings));
        }

        public void ValidatePassWhenLimitIsNotReached()
        {
            ODataValidationSettings settings = new ODataValidationSettings()
            {
                MaxTop = 10
            };

            _validator.Validate(new TopQueryOption("9", _context), settings);
        }

        public void Validate_DoesntThrowUnsortableException_ForUnsortableProperty_OnNonEmptyAllowedPropertiesList()
        {
            // Arrange : nonempty allowed orderby list
            ODataValidationSettings settings = new ODataValidationSettings();
            settings.AllowedOrderByProperties.Add("UnsortableProperty");

            // Act & Assert
            _validator.Validate(new OrderByQueryOption("UnsortableProperty asc", _context), settings);
        }

        public void Validate_ThrowsUnsortableException_ForUnsortableProperty_OnEmptyAllowedPropertiesList()
        {
            // Arrange : empty allowed orderby list
            ODataValidationSettings settings = new ODataValidationSettings();

            // Act & Assert
            Assert.Throws<ODataException>(() => _validator.Validate(new OrderByQueryOption("UnsortableProperty asc", _context), settings),
                "The property 'UnsortableProperty' cannot be used in the $orderby query option.");
        }

        public void ValidateThrowsOnUnsortable()
        {
            ODataValidationSettings settings = new ODataValidationSettings();
            settings.AllowedOrderByProperties.Add("UnsortableProperty");

            Assert.Throws<ODataException>(() =>
                _validator.Validate(new OrderByQueryOption("UnsortableProperty asc", _context), settings),
                "The property 'UnsortableProperty' cannot be used in the $orderby query option.");
        }

        public void Validate_DoesntThrowNotSortableException_ForNotSortableProperty_OnNonEmptyAllowedPropertiesList(string property)
        {
            // Arrange : nonempty allowed orderby list
            ODataValidationSettings settings = new ODataValidationSettings();
            settings.AllowedOrderByProperties.Add(property);

            // Act & Assert
            _validator.Validate(new OrderByQueryOption(String.Format("{0} asc", property), _context), settings);
        }

 public FilterQueryValidatorTest()
 {
     _validator = new MyFilterValidator();
     _builder = new ODataConventionModelBuilder();
     _builder.EntitySet<QueryCompositionCustomer>("Customer");
     _model = _builder.GetEdmModel();
     _settings = new ODataValidationSettings();
     _context = new ODataQueryContext(_model, typeof(QueryCompositionCustomer));
 }

        public void ValidatePassWhenLimitIsNotReached()
        {
            ODataValidationSettings settings = new ODataValidationSettings()
            {
                MaxSkip = 10
            };

            Assert.DoesNotThrow(() => _validator.Validate(new SkipQueryOption("9", _context), settings));
        }

        public void ValidateAllowsOrderByIt_IfExplicitlySpecified()
        {
            // Arrange
            OrderByQueryOption option = new OrderByQueryOption("$it", new ODataQueryContext(EdmCoreModel.Instance, typeof(int)), queryTranslator: null);
            ODataValidationSettings settings = new ODataValidationSettings { AllowedOrderByProperties = { "$it" } };

            // Act & Assert
            Assert.DoesNotThrow(() => _validator.Validate(option, settings));
        }

        public void ValidateAllowsOrderByIt()
        {
            // Arrange
            OrderByQueryOption option = new OrderByQueryOption("$it", _context);
            ODataValidationSettings settings = new ODataValidationSettings();

            // Act & Assert
            Assert.DoesNotThrow(() => _validator.Validate(option, settings));
        }

        public void ValidateAllowsOrderByIt()
        {
            // Arrange
            OrderByQueryOption option = new OrderByQueryOption("$it", new ODataQueryContext(EdmCoreModel.Instance, typeof(int)));
            ODataValidationSettings settings = new ODataValidationSettings();

            // Act & Assert
            Assert.DoesNotThrow(() => _validator.Validate(option, settings));
        }

 public void ValidatePassWhenLimitIsReached()
 {
     ODataValidationSettings settings = new ODataValidationSettings()
     {
         MaxSkip = 10
     };
     
     _validator.Validate(new SkipQueryOption("10", _context), settings);
 }

        public void ValidateThrowsWhenLimitIsExceeded()
        {
            ODataValidationSettings settings = new ODataValidationSettings()
            {
                MaxSkip = 10
            };

            Assert.Throws<ODataException>(() =>
                _validator.Validate(new SkipQueryOption("11", _context), settings));
        }

        public void Validate_ThrowsNotAllowedException_ForNotAllowedAndSortableLimitedProperty()
        {
            // Arrange
            ODataValidationSettings settings = new ODataValidationSettings();
            settings.AllowedOrderByProperties.Add("Name");

            // Act & Assert
            Assert.Throws<ODataException>(() => _validator.Validate(new OrderByQueryOption("UnsortableProperty asc", _context), settings),
                "Order by 'UnsortableProperty' is not allowed. To allow it, set the 'AllowedOrderByProperties' property on EnableQueryAttribute or QueryValidationSettings.");
        }

        public void ValidateWillAllowId()
        {
            // Arrange
            OrderByQueryOption option = new OrderByQueryOption("Id", _context);
            ODataValidationSettings settings = new ODataValidationSettings();
            settings.AllowedOrderByProperties.Add("Id");

            // Act & Assert
            Assert.DoesNotThrow(() => _validator.Validate(option, settings));
        }