@Test
    public void testReplaceMissingMappedValue() throws Exception
    {
        // Setup fixture.
        final Document doc = DocumentHelper.parseText("<vcard><el>{placeholder}</el></vcard>");
        final LdapVCardProvider.VCardTemplate template = new LdapVCardProvider.VCardTemplate(doc);
        final Map<String, String> attributes = new HashMap<>();

        // Execute system under test.
        final LdapVCardProvider.VCard vCard = new LdapVCardProvider.VCard(template);
        final Element result = vCard.getVCard(attributes);

        // Verify result.
        assertNotNull( result );
        assertEquals( "<vcard><el></el></vcard>", result.asXML() );
    }
Verifies that, using a simplified template, element values that are matched, but have no mapped value, get
replaced with an empty value.

@see <a href="https://igniterealtime.atlassian.net/browse/OF-2169">OF-2169</a>
xmppserver/src/test/java/org/jivesoftware/openfire/ldap/VCardTest.java