@Override
    Element servicesXml() {
        return parse(
                "<searchchains>",
                "  <searchchain id='federation1'>",
                "    <federation id='federationSearcher1'>",
                "      <source id='source1'>",
                "        <federationoptions optional='false' />",
                "      </source>",
                "    </federation>",
                "  </searchchain>",


                "  <provider id='provider1'>",
                "    <federationoptions optional='true' timeout='2.3 s' />",

                "    <source id='source1'>",
                "      <federationoptions timeout='12 ms' />",
                "    </source>",
                "    <source id='source2' />",
                "    <source id='sourceCommon' />",
                "  </provider>",

                "  <provider id='provider2' type='local' cluster='cluster1' />",

                "  <provider id='provider3'>",
                "    <source idref='sourceCommon' />",
                "  </provider>",

                "  <searchchain id='parentChain1' />",
                "</searchchains>");
    }
Test generated config for federation.
@author Tony Vaagenes
config-model/src/test/java/com/yahoo/vespa/model/container/search/searchchain/FederationTest.java