XMLUnit Demo...

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.blep</groupId>
    <artifactId>xmlunit-poc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>xmlunit</groupId>
            <artifactId>xmlunit</artifactId>
            <version>1.4</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

XmlUnitTest.java

package org.blep;

import org.custommonkey.xmlunit.Diff;
import org.custommonkey.xmlunit.Difference;
import org.custommonkey.xmlunit.DifferenceListener;
import org.junit.Test;
import org.w3c.dom.Node;

import static junit.framework.Assert.assertFalse;
import static org.custommonkey.xmlunit.XMLAssert.*;

/**
 * User: blep
 */

public class XmlUnitTest {
    private static String control ="<my:myXml xmlns:my='myUri' " +
            "xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' " +
            "xsi:schemaLocation='myUri http://somehost/my.xsd'>" +
            "<timestamp>1377064471255</timestamp>" +
            "<realBusinessValue>The Babel Tower</realBusinessValue>" +
            "</my:myXml>";

    private static String shouldBeSimilar ="<m:myXml xmlns:m='myUri' " +
            "xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' " +
            "xsi:schemaLocation='myUri http://somehost/my.xsd'>" +
            "<timestamp>137706447100</timestamp>" +
            "<realBusinessValue>The Babel Tower</realBusinessValue>" +
            "</m:myXml>";

    private static String different ="<my:myXml xmlns:my='myUri' " +
            "xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' " +
            "xsi:schemaLocation='myUri http://somehost/my.xsd'>" +
            "<timestamp>1377064471255</timestamp>" +
            "<realBusinessValue>The fake Babel Tower</realBusinessValue>" +
            "</my:myXml>";


    @Test
    public void should_be_identical() throws Exception {
        assertXMLIdentical(new Diff(control, control), true);
    }

    @Test
    public void should_be_similar() throws Exception {
        assertXMLEqual(control, control);
    }

    @Test
    public void should_not_be_equal() throws Exception {
        // timestamps and ns prefix differ, so they're not equal
        assertXMLNotEqual(control, shouldBeSimilar);
    }

    @Test
    public void make_notEquals_similar() throws Exception {
        final DifferenceListener dl = new DifferenceListener() {
            @Override
            public int differenceFound(Difference difference) {
                if(difference.getControlNodeDetail() == null ||
                        difference.getControlNodeDetail().getNode() == null ||
                        difference.getControlNodeDetail().getNode().getParentNode() == null)
                    return RETURN_ACCEPT_DIFFERENCE;
                else if (difference.getControlNodeDetail().getNode().getParentNode().getNodeName().equals("timestamp"))
                    return RETURN_IGNORE_DIFFERENCE_NODES_SIMILAR;
                return RETURN_ACCEPT_DIFFERENCE;
            }

            @Override
            public void skippedComparison(Node control, Node test) { }
        };
        //Same business value, different timestamp, different ns prefix => similar
        final Diff diff = new Diff(control, shouldBeSimilar);
        diff.overrideDifferenceListener(dl);
        assertXMLEqual(diff, true);

        // Same timestamp, same ns prefix, different business value => different
        final Diff diff1 = new Diff(control, different);
        diff1.overrideDifferenceListener(dl);
        assertFalse(diff1.similar());
    }
}