public String[] getDefaultCommandLineArgsArr(String inputSubDir, Path outputDir, Map<String, String> commandLine) throws Exception {
        List<String> args = new ArrayList<>();
        //need to include "-" because these are going to the commandline!
        if (inputSubDir != null) {
            args.add("-inputDir");
            args.add(getInputRoot(inputSubDir)
                    .toAbsolutePath()
                    .toString());
        }
        if (outputDir != null) {
            args.add("-outputDir");
            args.add(outputDir
                    .toAbsolutePath()
                    .toString());
        }
        if (commandLine != null) {
            for (Map.Entry<String, String> e : commandLine.entrySet()) {
                args.add(e.getKey());
                args.add(e.getValue());
            }
        }
        return args.toArray(new String[0]);
    }
helper method equivalent to File#listFiles()
grabs children only, does not walk recursively

@param p
@return
tika-batch/src/test/java/org/apache/tika/batch/fs/FSBatchTestBase.java