test: add feature and steps to test the XML report

- add new assertion steps to test the XML report, mostly based
  on XPath evaluated vis Saxon's API
- remove the xmlunit dependency that was not in use

pom.xml

@@ -170,12 +170,6 @@
             <artifactId>json-path-assert</artifactId>
             <version>2.8.0</version>
         </dependency>
-        <dependency>
-            <groupId>xmlunit</groupId>
-            <artifactId>xmlunit</artifactId>
-            <version>1.3</version>
-            <scope>test</scope>
-        </dependency>
         <dependency>
     	        <groupId>io.cucumber</groupId>
     	        <artifactId>cucumber-java</artifactId>

src/test/java/org/w3c/epubcheck/test/JSONReportAssertionSteps.java

@@ -19,7 +19,7 @@
 public class JSONReportAssertionSteps
 {
 
-  private TestReport report;
+  final private TestReport report;
 
   public JSONReportAssertionSteps(TestConfiguration configuration)
   {

src/test/java/org/w3c/epubcheck/test/XMLReportAssertionSteps.java

@@ -0,0 +1,115 @@
+package org.w3c.epubcheck.test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.emptyIterable;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.not;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.io.StringReader;
+import java.util.function.Supplier;
+
+import javax.xml.transform.stream.StreamSource;
+
+import io.cucumber.java.en.Given;
+import io.cucumber.java.en.Then;
+import net.sf.saxon.s9api.DocumentBuilder;
+import net.sf.saxon.s9api.Processor;
+import net.sf.saxon.s9api.SaxonApiException;
+import net.sf.saxon.s9api.XPathCompiler;
+import net.sf.saxon.s9api.XPathSelector;
+import net.sf.saxon.s9api.XdmNode;
+
+public class XMLReportAssertionSteps
+{
+
+  private final TestReport report;
+  private final Processor processor;
+  private final XPathCompiler xpathCompiler;
+  Supplier<XdmNode> xml = new Supplier<XdmNode>()
+  {
+    XdmNode xml = null;
+
+    @Override
+    public XdmNode get()
+    {
+      if (xml == null)
+      {
+
+        // Parse the XML report
+        DocumentBuilder docBuilder = processor.newDocumentBuilder();
+        try
+        {
+          xml = docBuilder.build(new StreamSource(new StringReader(report.getOutput())));
+        } catch (SaxonApiException e)
+        {
+          assertThat(e.getMessage(), false);
+        }
+      }
+      return xml;
+    }
+  };
+
+  public XMLReportAssertionSteps(TestConfiguration configuration)
+  {
+    this.report = configuration.getReport();
+
+    // Configure Saxon
+    this.processor = new Processor(false);
+    processor.getUnderlyingConfiguration()
+        .setStandardErrorOutput(new PrintStream(new OutputStream()
+        {
+          // TODO when upgrading to Java 11, replace by
+          // OutputStream#nullOutputStream()
+          @Override
+          public void write(int b)
+            throws IOException
+          {
+          }
+        }));
+    xpathCompiler = processor.newXPathCompiler();
+  }
+
+  @Given("the default namespace is {string}")
+  public void setDefaultNamespace(String namespace)
+  {
+    xpathCompiler.declareNamespace("", namespace);
+  }
+
+  @Then("the XML report is well-formed")
+  public void xmlIsWellFormed()
+  {
+    // Parsing errors would be raised in the constructor already
+  }
+
+  @Then("(the )XPath (value of ){string} is true")
+  public void xpathIsTrue(String xpath)
+    throws SaxonApiException
+  {
+    assertThat(eval(xpath).effectiveBooleanValue(), is(true));
+  }
+
+  @Then("(the )XPath {string} exists")
+  public void xpathExists(String xpath)
+    throws SaxonApiException
+  {
+    assertThat(eval(xpath), is(not(emptyIterable())));
+
+  }
+
+  private XPathSelector eval(String xpath)
+  {
+    try
+    {
+      XPathSelector result = xpathCompiler.compile(xpath).load();
+      result.setContextItem(xml.get());
+      return result;
+    } catch (SaxonApiException e)
+    {
+      throw new IllegalArgumentException(e);
+    }
+  }
+
+}

src/test/resources/reporting/xml-report.feature

@@ -0,0 +1,16 @@
+ Feature: EPUBCheck - XML Report tests
+
+  Checks the XML (JHove) report format
+
+
+  Background: 
+    Given EPUB test files located at '/reporting/files/'
+    And the reporting format is set to XML
+    And EPUBCheck with default settings
+    Given the default namespace is 'http://schema.openpreservation.org/ois/xml/ns/jhove'
+
+  Scenario: Basic well-formedness checks
+    When checking EPUB 'minimal'
+    Then the XML report is well-formed
+    And XPath '//repInfo' exists
+