[ejuf-cvs] ejuf/src/xdocs/htdocs/assertions-impl/convert-existing-ext index.xml,NONE,1.1

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Update of /cvsroot/ejuf/ejuf/src/xdocs/htdocs/assertions-impl/convert-existing-ext
In directory sc8-pr-cvs1:/tmp/cvs-serv14983/htdocs/assertions-impl/convert-existing-ext

Added Files:
	index.xml 
Log Message:
Updated information about JUnit and assertions class extension implementers

--- NEW FILE: index.xml ---
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE page PUBLIC "-//EJUF//Documentation DTD v1.0//EN"
    "http://ejuf.sourceforge.net/dtd/page-1.0.dtd">
<page xmlns="http://ejuf.sourceforge.net/ejuf-1.0" depth="2">
    <title>Converting existing JUnit extensions to EJUF extensions</title>
    <body xmlns="http://www.w3.org/1999/xhtml">
        <p>It really is quite easy to convert existing JUnit extensions.
            Especially if they extend TestCase.
        </p>
        <p>The easiest way to do this is to create a new interface and class
            paid which both extend some EJUF interfaces and classes.
        </p>
        <p>As an example, we will convert XMLUnit's XMLTestCase to an
            XMLTestCaseWrapperAssertions in EJUF.  If you cannnot wait and
            must see the converted class, take a look at the
            <code>ejuf.ext.assertions.XMLTestCaseWrapperAssertions</code> class.
        </p>
        <h2>Creating the interface to XMLTestCase</h2>
        <p>
            First off, we will start by creating the interface to the
            XMLTestCase.  Take a look at this:
        </p>
<java xmlns="http://ejuf.sourceforge.net/ejuf-1.0">
package org.custommonkey.xmlunit.ext.ejuf;

public interface <link>ejuf/ext/assertions/XMLTestCaseWrapperAssertions</link> extends <link>ejuf/assertions/Assertions</link>, XSLTConstants {
    void assertXMLEqual(String s, Diff diff, boolean b);

    ...
}
</java>
        <p>
            What we have done here is to declare an interface that users of
            XMLUnit will need to implement.  This is the same kind of interface
            than EqualityAssertions or FailureAssertions that EJUF provides
            by default.
        </p>
        <h2>Creating the interface implementation</h2>
        <p>
            Next, we have to create an implementation of this interface which
            provides the services to the users.  Ideally, we want to do the
            minimum amount of work which will bring us to the desired point
            of functionnality ( lazy users :) ).  So, we declare the type:
        </p>
<java xmlns="http://ejuf.sourceforge.net/ejuf-1.0">
package org.custommonkey.xmlunit.ext.ejuf;

public class XMLTestCaseAssertionsImpl extends <link>ejuf/assertions/AssertionServices</link>
        implements XMLTestCaseAssertions {
    private static final XMLTestCase xmlTestCase = new XMLTestCase("null");

    public void assertXMLEqual(String s, Diff diff, boolean b) {
        xmlTestCase.assertXMLEqual(s, diff, b);
    }

    ...
}
</java>
        <p>
            Notice that we have reused the XMLTestCase as-is.  No modifications
            were necessary.  We only added a layer of indirection so that users
            may call into the test case abstractly from any test instance.
        </p>
        <h2>Update implementation to generate events about assertions</h2>
        <p>
            Finally, the last thing to do is to implement the assertion
            notification function.  The following is a first draft of such
            functionnality:
        </p>
<java xmlns="http://ejuf.sourceforge.net/ejuf-1.0">
package org.custommonkey.xmlunit.ext.ejuf;

public class XMLTestCaseAssertionsImpl extends <link>ejuf/assertions/AssertionServices</link>
        implements XMLTestCaseAssertions {
    private final <link>ejuf/assertions/AssertionsRegistry</link> registry;
    ...

    public XMLTestCaseAssertionsImpl(final <link>ejuf/assertions/AssertionsRegistry</link> registry) {
        this.registry = registry;
    }

    public void assertXMLEqual(String s, Diff diff, boolean b) {
        xmlTestCase.assertXMLEqual(s, diff, b);
        registry.assertion(new AssertionError("Comparing differences: "
                + diff.toString()));
    }

    ...
}
</java>
        <p>
            As you may have noticed, the part about the registry was added in
            the XMLTestCaseAssertionsImpl.  This means that the same
            XMLTestCase can be used <strong>both</strong> by JUnit and by EJUF
            users...  This is an extra bonus for extension developers.
        </p>
    </body>

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