@Test
    public void testStripPrefixFreeCanonicalization() throws Exception
    {
        // Setup fixture.
        final String input = "<stream:stream to='example.com' xmlns:stream='http://etherx.jabber.org/streams' version='1.0'><message xmlns='jabber:client' from='juliet@example.com' to='romeo@example.net' xml:lang='en'><body>Art thou not Romeo, and a Montague?</body></message></stream:stream>";

        // Execute system under test.
        final Document result = packetReader.read( new StringReader( input ) );

        // Verify result.
        assertFalse( result.asXML().contains( "jabber:client" ) );
    }
Check if the 'jabber:client' default namespace declaration is stripped from a stanza.

Openfire strips this namespace (among others) to make the resulting XML 're-usable', in context of the
implementation note in RFC 6120, section 4.8.3.

@see <a href="https://xmpp.org/rfcs/rfc6120.html#streams-ns-xmpp">RFC 6120, 4.8.3. XMPP Content Namespaces</a>
xmppserver/src/test/java/dom/io/XMPPPacketReaderTest.java