public static File getCfgDir() {
        String token = Long.toHexString(random.nextLong());
        File cfgDir = new File(topCfgDir + File.separator + token + File.separator);
        cfgDir.mkdirs();
        return cfgDir;
    }
Copies src file to dst file. If the dst file does not exist, it is created.
container-search/src/test/java/com/yahoo/search/searchchain/config/test/SearchChainConfigurerTestCase.java