private static File newFolder(File root, String... subDirs) throws IOException {
        String subFolder = String.join("/", subDirs);
        File result = new File(root, subFolder);
        if (!result.mkdirs()) {
            throw new IOException("Couldn't create folders " + root);
        }
        return result;
    }
Tests that config definitions with namespace are treated properly when they have the format
as in the config definitions dir ($VESPA_HOME/share/vespa/configdefinitions on a machine
with Vespa packages installed) (does not test when read from user def files). Also tests a config
definition without version in file name
config-model/src/test/java/com/yahoo/config/model/ApplicationDeployTest.java