private String extractId(String xmlStringWithIdAttribute) {
        int idStart = xmlStringWithIdAttribute.indexOf("id=");
        int idEnd = Math.min(xmlStringWithIdAttribute.indexOf(" ", idStart),
                             xmlStringWithIdAttribute.indexOf(">", idStart));
        return xmlStringWithIdAttribute.substring(idStart + 4, idEnd - 1);
    }
Additional (mock) files that will exist in this application package, with their content.
config-model/src/main/java/com/yahoo/config/model/test/MockApplicationPackage.java