@Override
    public void validateXML() {
        if (failOnValidateXml) {
            throw new IllegalArgumentException("Error in application package");
        } else {
            throw new UnsupportedOperationException("This application package cannot validate XML");
        }
    }
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