XMLUnit is a library that supports testing XML output in several ways.

XMLUnit 2.x is a complete rewrite of XMLUnit and actually doesn't share any code with XMLUnit for Java 1.x.

Some goals for XMLUnit 2.x:

• create .NET and Java versions that are compatible in design while trying to be idiomatic for each platform
• remove all static configuration (the old XMLUnit class setter methods)
• focus on the parts that are useful for testing
  • XPath
  • (Schema) validation
  • comparisons
• be independent of any test framework

XMLUnit 1.x is no longer maintained, you can still find the old forum over at sourceforge and we still use the sourceforge provided mailing list.

• Developer Guide
• User's Guide

If you are looking for something to work on, we've compiled a list of known issues.

Please see the contributing guide for details on how to contribute.

The latest releases are available as GitHub releases or via Maven Central.

The core library is

<dependency>
  <groupId>org.xmlunit</groupId>
  <artifactId>xmlunit-core</artifactId>
  <version>x.y.z</version>
</dependency>

We are providing SNAPSHOT builds from Sonatypes OSS Nexus Repository, you need to add

<repository>
  <id>snapshots-repo</id>
  <url>https://oss.sonatype.org/content/repositories/snapshots</url>
  <releases><enabled>false</enabled></releases>
  <snapshots><enabled>true</enabled></snapshots>
</repository>

to your Maven settings.

These are some really small examples, more is available as part of the user guide

Source control = Input.fromFile("test-data/good.xml").build();
Source test = Input.fromByteArray(createTestDocument()).build();
DifferenceEngine diff = new DOMDifferenceEngine();
diff.addDifferenceListener(new ComparisonListener() {
        public void comparisonPerformed(Comparison comparison, ComparisonResult outcome) {
            Assert.fail("found a difference: " + comparison);
        }
    });
diff.compare(control, test);

or using the fluent builder API

Diff d = DiffBuilder.compare(Input.fromFile("test-data/good.xml"))
             .withTest(createTestDocument()).build();
assert !d.hasDifferences();

or using Hamcrest with CompareMatcher

import static org.xmlunit.matchers.CompareMatcher.isIdenticalTo;
...

assertThat(createTestDocument(), isIdenticalTo(Input.fromFile("test-data/good.xml")));

or using AssertJ with XmlAssert of the xmlunit-assertj module

import static org.xmlunit.assertj.XmlAssert.assertThat;
...

assertThat(createTestDocument())
            .and(Input.fromFile("test-data/good.xml"))
            .areIdentical();

or using AssertJ with XmlAssert of the xmlunit-assertj3 module

import static org.xmlunit.assertj3.XmlAssert.assertThat;
...

assertThat(createTestDocument())
            .and(Input.fromFile("test-data/good.xml"))
            .areIdentical();

Source source = Input.fromString("<foo>bar</foo>").build();
XPathEngine xpath = new JAXPXPathEngine();
Iterable<Node> allMatches = xpath.selectNodes("/foo", source);
assert allMatches.iterator().hasNext();
String content = xpath.evaluate("/foo/text()", source);
assert "bar".equals(content);

or using Hamcrest with HasXPathMatcher, EvaluateXPathMatcher

assertThat("<foo>bar</foo>", HasXPathMatcher.hasXPath("/foo"));
assertThat("<foo>bar</foo>", EvaluateXPathMatcher.hasXPath("/foo/text()",
                                                           equalTo("bar")));

or using AssertJ with XmlAssert of the xmlunit-assertj module

import static org.xmlunit.assertj.XmlAssert.assertThat;
...

assertThat("<foo>bar</foo>").hasXPath("/foo");
assertThat("<foo>bar</foo>").valueByXPath("/foo/text()").isEqualTo("bar");

or using AssertJ with XmlAssert of the xmlunit-assertj3 module

import static org.xmlunit.assertj3.XmlAssert.assertThat;
...

assertThat("<foo>bar</foo>").hasXPath("/foo");
assertThat("<foo>bar</foo>").valueByXPath("/foo/text()").isEqualTo("bar");

Validator v = Validator.forLanguage(Languages.W3C_XML_SCHEMA_NS_URI);
v.setSchemaSources(Input.fromUri("http://example.com/some.xsd").build(),
                   Input.fromFile("local.xsd").build());
ValidationResult result = v.validateInstance(Input.fromDocument(createDocument()).build());
boolean valid = result.isValid();
Iterable<ValidationProblem> problems = result.getProblems();

or using Hamcrest with ValidationMatcher

import static org.xmlunit.matchers.ValidationMatcher.valid;
...

assertThat(createDocument(), valid(Input.fromFile("local.xsd")));

or using AssertJ with XmlAssert of the xmlunit-assertj module

import static org.xmlunit.assertj.XmlAssert.assertThat;
...

assertThat(createDocument()).isValidAgainst(Input.fromFile("local.xsd"));

or using AssertJ with XmlAssert of the xmlunit-assertj3 module

import static org.xmlunit.assertj3.XmlAssert.assertThat;
...

assertThat(createDocument()).isValidAgainst(Input.fromFile("local.xsd"));

Starting with version 2.8.0 XMLUnit requires Java 7, which has always been the minimum requirement for the AssertJ module. All other modules in versions 2.0.0 to 2.7.0 required Java 6. The xmlunit-assertj3 module requires Java 8 as does AssertJ 3.x itself.

The core library provides all functionality needed to test XML output and hasn't got any dependencies. It uses JUnit 4.x for its own tests.

If you want to use Input.fromJaxb - i.e. you want to serialize plain Java objects to XML as input - then you may also need to add a dependency on the JAXB implementation. For more details see the User's Guide.

The core library is complemented by Hamcrest 1.x matchers and AssertJ assertions. There also exists a legacy project that provides the API of XMLUnit 1.x on top of the 2.x core library.

While the Hamcrest matchers are built against Hamcrest 1.x they are supposed to work with Hamcrest 2.x as well.

Starting with XMLUnit 2.8.1 there are two different AssertJ modules, xmlunit-assertj is the original implementation which is based on AssertJ 2.x and also works for AssertJ 3.x but uses reflection to deal with some changes in later versions of AssertJ. The xmlunit-assertj3 module requires at least AssertJ 3.18.1.

The xmlunit-assertj module depends on an internal package not exported by AssertJ's OSGi module and thus doesn't work in an OSGi context.

Another difference between the two AssertJ modules is the exception thrown if a comparison fails. xmlunit-assertj will try to throw a JUnit 4.x ComparisonFailure if the class is available and thus is best suited for tests using JUnit 4.x. xmlunit-assertj3 will try to throw an Open Test Alliance AssertionFailedError if the class is available and thus is better suited for tests using JUnit 5.x.

XMLUnit for Java uses a git submodule for test resources it shares with XMLUnit.NET. You can either clone this repository using git clone --recursive or run git submodule update --init inside your fresh working copy after cloning normally.

If you have checked out a working copy before we added the submodule, you'll need to run git submodule update --init once.

XMLUnit for Java builds using Apache Maven 3.x, mainly you want to run

$ mvn install

in order to compile all modules and run the tests.