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Add option to ignore child ordering in comparisons (#4)
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9 files changed

+421
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‎project/plugins.sbt

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@@ -14,3 +14,4 @@ addSbtPlugin("com.eed3si9n" % "sbt-unidoc" % "0.4.2")
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addSbtPlugin("com.typesafe.sbt" % "sbt-ghpages" % "0.6.3")
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addSbtPlugin("com.typesafe.sbt" % "sbt-site" % "1.4.0")
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addSbtPlugin("com.lightbend.paradox" % "sbt-paradox" % "0.6.5")
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addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "3.0.0")

‎src/main/paradox/comparing-xml.md

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@@ -124,4 +124,51 @@ XmlDiffers(
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Seq("second", "first"),
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Seq("test")
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)
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```
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```
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### IgnoreChildOrder
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If enabled the ordering of child elements will be ignored. This is handled by re-ordering child nodes using an arbitrary
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sorting algorithm before comparing them.
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_Note: the first difference returned may be different if this option is enabled._
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#### Example 1
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This:
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```xml
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<example>
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<child-1/>
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<child-2/>
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</example>
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```
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would be considered equal to:
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```xml
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<example>
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<child-2/>
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<child-1/>
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</example>
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```
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#### Example 2
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This:
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```xml
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<example>
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<child-1 attribute1="value-1" attribute2="value-2"/>
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<child-2 attribute="something"/>
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</example>
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```
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would be considered equal to:
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```xml
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<example>
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<child-2 attribute="something"/>
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<child-1 attribute2="value-2" attribute1="value-1" />
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</example>
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```
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_(The ordering of nodes and attributes are both ignored)_

‎xml-compare/src/main/scala/software/purpledragon/xml/XmlUtils.scala

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/*
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* Copyright 2017 Michael Stringer
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package software.purpledragon.xml
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import scala.xml.Node
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/**
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* Utilities for dealing with XML.
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*/
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object XmlUtils {
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/**
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* Extracts names of attributes and a map of attributes from an XML [[scala.xml.Node Node]].
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*
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* @param node the XML node to extract attributes for.
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* @return a sequence of attribute names and a map of attribute values.
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*/
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def extractAttributes(node: Node): (Seq[String], Map[String, String]) = {
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node.attributes.foldLeft(Seq.empty[String], Map.empty[String, String]) {
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case ((keys, attribs), attrib) =>
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(keys :+ attrib.key, attribs + (attrib.key -> attrib.value.text))
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}
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}
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}

‎xml-compare/src/main/scala/software/purpledragon/xml/compare/NormalisedNodeOrdering.scala

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/*
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* Copyright 2017 Michael Stringer
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package software.purpledragon.xml.compare
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import software.purpledragon.xml.XmlUtils.extractAttributes
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import scala.xml._
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/**
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* Arbitrary ordering for XML nodes used to normalise XML when we are ignoring child ordering.
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*/
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private[compare] object NormalisedNodeOrdering extends Ordering[Node] {
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private def typeToOrdering(node: Node): Int = {
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node match {
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case _: Elem => 1
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case _: Text => 2
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case _: PCData => 3
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case _: Comment => 4
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}
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}
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override def compare(x: Node, y: Node): Int = {
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(x, y) match {
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case (xe: Elem, ye: Elem) =>
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val labelOrder = xe.label compareTo ye.label
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if (labelOrder != 0) {
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labelOrder
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} else {
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val (xAttributeNames, xAttributes) = extractAttributes(xe)
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val (yAttributeNames, yAttributes) = extractAttributes(ye)
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// order by attribute count
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val attributeSizeOrder = xAttributeNames.size compareTo yAttributeNames.size
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if (attributeSizeOrder != 0) {
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attributeSizeOrder
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} else {
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// compare attribute names
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val attributeNamesOrder = xAttributeNames.sorted zip yAttributeNames.sorted map {
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case (x, y) => x compareTo y
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}
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// take first difference
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attributeNamesOrder.find(_ != 0) match {
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case Some(v) =>
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v
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case None =>
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// if not compare values
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val attributeValuesOrder = xAttributeNames map { name =>
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xAttributes(name) compareTo yAttributes(name)
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}
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attributeValuesOrder.find(_ != 0).getOrElse(0)
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}
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}
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}
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case (xe: Text, ye: Text) =>
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xe.text compareTo ye.text
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case (xe: PCData, ye: PCData) =>
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xe.data compareTo ye.data
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case (xe: Comment, ye: Comment) =>
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xe.commentText compareTo ye.commentText
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case _ =>
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// different types - order by type
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typeToOrdering(x) compareTo typeToOrdering(y)
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}
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}
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}

‎xml-compare/src/main/scala/software/purpledragon/xml/compare/XmlCompare.scala

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@@ -16,17 +16,20 @@
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package software.purpledragon.xml.compare
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import software.purpledragon.xml.XmlUtils.extractAttributes
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import software.purpledragon.xml.compare.options.DiffOption._
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import software.purpledragon.xml.compare.options.DiffOptions
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import software.purpledragon.xml.compare.options.{DiffOption, DiffOptions}
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import scala.xml.{Atom, Node}
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import scala.xml._
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/**
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* Utility for comparing XML documents.
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*/
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object XmlCompare {
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private type Check = (Node, Node, DiffOptions, Seq[String]) => XmlDiff
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private implicit val NodeOrdering = NormalisedNodeOrdering
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/**
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* Default [[software.purpledragon.xml.compare.options.DiffOption.DiffOption DiffOption]]s to use during XML comparison.
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*
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}
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private def compareAttributes(left: Node, right: Node, options: DiffOptions, path: Seq[String]): XmlDiff = {
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def extractAttributes(node: Node): (Seq[String], Map[String, String]) = {
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node.attributes.foldLeft(Seq.empty[String], Map.empty[String, String]) {
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case ((keys, attribs), attrib) =>
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(keys :+ attrib.key, attribs + (attrib.key -> attrib.value.text))
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}
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}
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val (leftKeys, leftMap) = extractAttributes(left)
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val (rightKeys, rightMap) = extractAttributes(right)
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@@ -115,8 +111,8 @@ object XmlCompare {
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}
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private def compareChildren(left: Node, right: Node, options: DiffOptions, path: Seq[String]): XmlDiff = {
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val leftChildren = left.child.filterNot(c => c.isInstanceOf[Atom[_]])
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val rightChildren = right.child.filterNot(c => c.isInstanceOf[Atom[_]])
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val leftChildren = normalise(left.child, options)
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val rightChildren = normalise(right.child, options)
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if (leftChildren.size != rightChildren.size) {
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XmlDiffers("different child count", leftChildren.size, rightChildren.size, extendPath(path, left))
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private def extendPath(path: Seq[String], node: Node): Seq[String] = {
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path :+ node.nameToString(new StringBuilder()).toString
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}
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private def normalise(nodes: Seq[Node], options: DiffOptions): Seq[Node] = {
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val sort = options.contains(DiffOption.IgnoreChildOrder)
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val filtered = nodes.filterNot(n => n.isInstanceOf[Atom[_]])
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if (sort) {
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filtered.sorted
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} else {
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filtered
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}
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}
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}

‎xml-compare/src/main/scala/software/purpledragon/xml/compare/options/DiffOption.scala

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@@ -63,4 +63,24 @@ object DiffOption extends Enumeration {
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* }}}
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*/
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val StrictAttributeOrdering: DiffOption.Value = Value
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/**
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* Ignores the ordering of XML elements.
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*
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* Enabling this makes this:
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* {{{
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* <example>
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* <child-1/>
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* <child-2/>
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* </example>
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* }}}
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* equal to:
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* {{{
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* <example>
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* <child-2/>
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* <child-1/>
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* </example>
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* }}}
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*/
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val IgnoreChildOrder: DiffOption.Value = Value
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}

‎xml-compare/src/test/scala/software/purpledragon/xml/XmlUtilsSpec.scala

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/*
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* Copyright 2017 Michael Stringer
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package software.purpledragon.xml
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import org.scalatest.{FlatSpec, Matchers}
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class XmlUtilsSpec extends FlatSpec with Matchers {
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"XmlUtils.extractAttributes" should "return empty values for no attributes" in {
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XmlUtils.extractAttributes(<empty/>) shouldBe (Nil, Map.empty[String, String])
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}
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it should "return attribute names and value map" in {
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val (names, attributes) = XmlUtils.extractAttributes(<test field3="value-3" field1="value-1" field2="value-2"/>)
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names shouldBe Seq("field3", "field1", "field2")
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attributes shouldBe Map(
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"field1" -> "value-1",
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"field2" -> "value-2",
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"field3" -> "value-3"
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)
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}
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}

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