add a new XmlWhitespaceStrippedSource that honors XML's idea of whitespace

see https://github.com/xmlunit/xmlunit/issues/260

Author: bodewig

RELEASE_NOTES.md

@@ -12,6 +12,12 @@
   [#38](https://github.com/xmlunit/xmlunit.net/issues/38). And neither
   of the methods could deal with `XmlSignificantWhitespace` at all.
 
+* add `XmlWhitespaceStrippedSource` that only trims characters that
+  are considered whitespace by the [XML
+  Specification](https://www.w3.org/TR/xml11/#NT-S) from textual
+  content.
+  Issue [xmlunit/#260](https://github.com/xmlunit/xmlunit/issues/260).
+
 ## XMLUnit.NET 2.9.2 - /Released 2023-03-16/
 
 * added `NodeFilters#SatisfiesAll` and `SatifiesAny` methods to make

src/main/net-core/Input/XmlWhitespaceStrippedSource.cs

@@ -0,0 +1,43 @@
+/*
+  This file is licensed to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+using Org.XmlUnit.Util;
+
+namespace Org.XmlUnit.Input {
+
+    /// <summary>
+    /// A source that is obtained from a different source by removing
+    /// all empty text nodes and removing all characters XML considers
+    /// whitespace at the start and end of the text content of the
+    /// non-empty ones. <see href="https://www.w3.org/TR/xml11/#NT-S"/>
+    /// </summary>
+    /// <remarks>
+    ///   <para>
+    /// If you only want to remove text nodes consisting solely of
+    /// whitespace (AKA element content whitespace) but leave all
+    /// other text nodes alone you should use
+    /// ElementContentWhitespaceStrippedSource instead.
+    ///   </para>
+    /// </remarks>
+    public class XmlWhitespaceStrippedSource : DOMSource {
+        /// <summary>
+        /// Creates a new Source with the same content as another source trimming whitespace from Text nodes.
+        /// </summary>
+        /// <param name="originalSource">source with the original content</param>
+        public XmlWhitespaceStrippedSource(ISource originalSource) :
+            base(Nodes.StripXmlWhitespace(originalSource.ToDocument())) {
+            SystemId = originalSource.SystemId;
+        }
+    }
+}

src/main/net-core/NetFramework/XMLUnit.Core.NetFramework.csproj

@@ -110,6 +110,7 @@
     <Compile Include="..\Input\StringSource.cs" />
     <Compile Include="..\Input\WhitespaceNormalizedSource.cs" />
     <Compile Include="..\Input\WhitespaceStrippedSource.cs" />
+    <Compile Include="..\Input\XmlWhitespaceStrippedSource.cs" />
     <Compile Include="..\ISource.cs" />
     <Compile Include="..\Transform\Transformation.cs" />
     <Compile Include="..\Util\Convert.cs" />

src/main/net-core/Util/Nodes.cs

@@ -84,7 +84,22 @@ public static IDictionary<XmlQualifiedName, string>
         public static XmlNode StripWhitespace(XmlNode original) {
             XmlNode cloned = original.CloneNode(true);
             cloned.Normalize();
-            HandleWsRec(cloned, false);
+            HandleWsRec(cloned, TrimValue);
+            return cloned;
+        }
+
+        /// <summary>
+        /// Creates a new Node (of the same type as the original node)
+        /// that is similar to the orginal but doesn't contain any
+        /// empty text or CDATA nodes and where all textual content
+        /// including attribute values or comments are trimmed of
+        /// characters XML considers whitespace according to
+        /// <see href="https://www.w3.org/TR/xml11/#NT-S"/>.
+        /// </summary>
+        public static XmlNode StripXmlWhitespace(XmlNode original) {
+            XmlNode cloned = original.CloneNode(true);
+            cloned.Normalize();
+            HandleWsRec(cloned, XmlTrimValue);
             return cloned;
         }
 
@@ -104,7 +119,7 @@ public static XmlNode StripWhitespace(XmlNode original) {
         public static XmlNode NormalizeWhitespace(XmlNode original) {
             XmlNode cloned = original.CloneNode(true);
             cloned.Normalize();
-            HandleWsRec(cloned, true);
+            HandleWsRec(cloned, TrimAndNormalizeValue);
             return cloned;
         }
 
@@ -129,23 +144,44 @@ public static XmlNode StripElementContentWhitespace(XmlNode original) {
             return cloned;
         }
 
+        /// <summary>
+        /// Returns the nodes' value trimmed of all whitespace.
+        /// <summary>
+        private static String TrimValue(XmlNode n) {
+            return n.Value.Trim();
+        }
+
+        /// <summary>
+        /// Returns the nodes' value trimmed of all whitespace and Normalized
+        /// <summary>
+        private static String TrimAndNormalizeValue(XmlNode n) {
+            return Normalize(TrimValue(n));
+        }
+
+        private static readonly char[] XML_WHITESPACE_CHARS = {
+            ' ', '\r', '\n', '\t'
+        };
+
+        /// <summary>
+        /// Returns the nodes' value trimmed of all characters XML considers whitespace.
+        /// <summary>
+        private static String XmlTrimValue(XmlNode n) {
+            return n.Value.Trim(XML_WHITESPACE_CHARS);
+        }
+
         /// <summary>
         /// Trims textual content of this node, removes empty text and
         /// CDATA children, recurses into its child nodes.
         /// </summary>
         /// <parameter name="normalize">whether to normalize
         /// whitespace as well</parameter>
-        private static void HandleWsRec(XmlNode n, bool normalize) {
+        private static void HandleWsRec(XmlNode n, Func<XmlNode, String> handleWs) {
             if (n is XmlCharacterData || n is XmlProcessingInstruction) {
-                string s = n.Value.Trim();
-                if (normalize) {
-                    s = Normalize(s);
-                }
-                n.Value = s;
+                n.Value = handleWs(n);
             }
             LinkedList<XmlNode> toRemove = new LinkedList<XmlNode>();
             foreach (XmlNode child in n.ChildNodes) {
-                HandleWsRec(child, normalize);
+                HandleWsRec(child, handleWs);
                 if (!(n is XmlAttribute)
                     && IsTextualContentNode(child)
                     && child.Value.Length == 0) {
@@ -158,7 +194,7 @@ private static void HandleWsRec(XmlNode n, bool normalize) {
             XmlNamedNodeMap attrs = n.Attributes;
             if (attrs != null) {
                 foreach (XmlAttribute a in attrs) {
-                    HandleWsRec(a, normalize);
+                    HandleWsRec(a, handleWs);
                 }
             }
         }

src/tests/net-core/Input/WhitespaceStrippedSourceTest.cs

@@ -35,7 +35,7 @@ public void WhitespaceIsStrippedProperlyEvenWithPreserveWhitespaceDoc() {
         }
 
         private void WhitespaceIsStrippedProperly(XmlDocument testDoc) {
-            string testXml = "<a>\n <b>\n  Test Value\n </b>\n</a>";
+            string testXml = "<a>\n <b>\n  Test Value\u00a0\n </b>\n</a>";
             testDoc.LoadXml(testXml);
             WhitespaceStrippedSource s = new WhitespaceStrippedSource(new DOMSource(testDoc));
             XmlNode root = s.Node;

src/tests/net-core/Input/XmlWhitespaceStrippedSourceTest.cs

@@ -0,0 +1,49 @@
+/*
+  This file is licensed to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+using System.Xml;
+using Org.XmlUnit.Util;
+using NUnit.Framework;
+
+namespace Org.XmlUnit.Input {
+
+    [TestFixture]
+    public class XmlWhitespaceStrippedSourceTest {
+
+        [Test]
+        public void XmlWhitespaceIsStrippedProperly() {
+            XmlWhitespaceIsStrippedProperly(new XmlDocument());
+        }
+
+        [Test]
+        public void XmlWhitespaceIsStrippedProperlyEvenWithPreserveWhitespaceDoc() {
+            XmlDocument testDoc = new XmlDocument();
+            testDoc.PreserveWhitespace = true;
+            XmlWhitespaceIsStrippedProperly(testDoc);
+        }
+
+        private void XmlWhitespaceIsStrippedProperly(XmlDocument testDoc) {
+            string testXml = "<a>\n <b>\n  Test Value\u00a0\n </b>\n</a>";
+            testDoc.LoadXml(testXml);
+            XmlWhitespaceStrippedSource s = new XmlWhitespaceStrippedSource(new DOMSource(testDoc));
+            XmlNode root = s.Node;
+            Assert.AreEqual(1, root.ChildNodes.Count);
+            XmlNode a = root.FirstChild;
+            Assert.AreEqual(1, a.ChildNodes.Count);
+            XmlNode b = a.FirstChild;
+            Assert.AreEqual(1, b.ChildNodes.Count);
+            Assert.AreEqual("Test Value\u00a0", b.FirstChild.Value);
+        }
+    }
+}

src/tests/net-core/NetFramework/XMLUnit.Core.Tests.NetFramework.csproj

@@ -87,6 +87,7 @@
     <Compile Include="..\Input\CommentLessSourceTest.cs" />
     <Compile Include="..\Input\NormalizedSourceTest.cs" />
     <Compile Include="..\Input\WhitespaceStrippedSourceTest.cs" />
+    <Compile Include="..\Input\XmlWhitespaceStrippedSourceTest.cs" />
     <Compile Include="..\TestResources.cs" />
     <Compile Include="..\Transform\TransformationTest.cs" />
     <Compile Include="..\Util\ConvertTest.cs" />

src/tests/net-core/Util/NodesTest.cs

@@ -135,7 +135,7 @@ [Test] public void AttributeMapWithFilter() {
         private XmlDocument HandleWsSetup() {
             return Convert.ToDocument(InputBuilder.FromString(
                 "<root>\n"
-                + "<!-- trim\tme -->\n"
+                + "<!--\u00a0 trim\tme\u00a0 -->\n"
                 + "<child attr=' trim me ' attr2='not me'>\n"
                 + " trim me \n"
                 + "</child><![CDATA[ trim me ]]>\n"
@@ -156,11 +156,22 @@ private KeyValuePair<XmlDocument, XmlNode> NormalizeWsSetup() {
                 XmlNode>(toTest, Nodes.NormalizeWhitespace(toTest));
         }
 
+        private KeyValuePair<XmlDocument, XmlNode> StripXmlWsSetup() {
+            XmlDocument toTest = HandleWsSetup();
+            return new KeyValuePair<XmlDocument,
+                XmlNode>(toTest, Nodes.StripXmlWhitespace(toTest));
+        }
+
         [Test]
         public void StripWhitespaceWorks() {
             HandleWsWorks(StripWsSetup(), "trim\tme");
         }
 
+        [Test]
+        public void StripXmlWhitespaceWorks() {
+            HandleWsWorks(StripXmlWsSetup(), "\u00a0 trim\tme\u00a0");
+        }
+
         [Test]
         public void NormalizeWhitespaceWorks() {
             HandleWsWorks(NormalizeWsSetup(), "trim me");
@@ -209,6 +220,11 @@ public void StripWhitespaceDoesntAlterOriginal() {
             HandleWsDoesntAlterOriginal(StripWsSetup());
         }
 
+        [Test]
+        public void StripXmlWhitespaceDoesntAlterOriginal() {
+            HandleWsDoesntAlterOriginal(StripXmlWsSetup());
+        }
+
         [Test]
         public void NormalizeWhitespaceDoesntAlterOriginal() {
             HandleWsDoesntAlterOriginal(NormalizeWsSetup());
@@ -224,7 +240,7 @@ private void HandleWsDoesntAlterOriginal(KeyValuePair<XmlDocument,
             Assert.AreEqual(5, rootsChildren.Count);
             Assert.IsTrue(rootsChildren[0] is XmlComment,
                           "should be comment, is " + rootsChildren[0].GetType());
-            Assert.AreEqual(" trim\tme ",
+            Assert.AreEqual("\u00a0 trim\tme\u00a0 ",
                             ((XmlComment) rootsChildren[0]).Data);
             Assert.IsTrue(rootsChildren[1] is XmlElement,
                           "should be element, is " + rootsChildren[1].GetType());
@@ -277,7 +293,7 @@ public void StripECWWorks() {
             Assert.AreEqual(4, rootsChildren.Count);
             Assert.IsTrue(rootsChildren[0] is XmlComment,
                           "should be comment, is " + rootsChildren[0].GetType());
-            Assert.AreEqual(" trim\tme ",
+            Assert.AreEqual("\u00a0 trim\tme\u00a0 ",
                             ((XmlComment) rootsChildren[0]).Data);
             Assert.IsTrue(rootsChildren[1] is XmlElement,
                           "should be element, is " + rootsChildren[1].GetType());