private String createProtonStreamingVespaServices(List<String> sdNames) {
        String pre = "<?xml version='1.0' encoding='utf-8' ?>" +
                "<services version='1.0'>" +
                "  <admin version='2.0'>" +
                "    <adminserver hostalias='node0'/>" +
                "  </admin>" +
                "  <container version='1.0'>" +
                "    <search/>" +
                "    <nodes>" +
                "      <node hostalias='node0'/>" +
                "    </nodes>" +
                "  </container>" +
                "  <content version='1.0' id='test'>" +
                "     <redundancy>1</redundancy>\n" +
                "     <engine>" +
                "       <proton/>" +
                "     </engine>" +
                "     <documents>";
        String post =
                "         </documents>" +
                        "     <group>" +
                        "       <node hostalias='node0' distribution-key='3' />" +
                        "     </group>" +
                        "</content>" +
                        "</services>";
        return createVespaServices(pre, sdNames, post, "streaming");
    }
Test for using the content model to create indexed search clusters.
config-model/src/test/java/com/yahoo/vespa/model/content/IndexedTest.java