[ruby-core:35294] A patch for parallel test-all running

(I sent a mail with Japanese to ruby-dev before. Please ignore this mail
 if you had same mail already; it's [ruby-dev:43222])

Hi,

I started writing a patch about parallel running for test-all of ruby about
3 days ago.

And I succeed running test-all parallel yesterday, I decide to send a mail to
ruby-{dev,core} for reviewing.

This mail is for reviewing patch, so I'll create a feature ticket if a patch
behavior approached to my ideal.

So, I'm waiting comments, reports for this patch.

(I haven't checked any environments without mine, so I'm waiting for tester
 too. I wanna a report at Windows)

## The Patch

Latest branch for development:
  https://github.com/sorah/ruby/compare/master...parallel_test
Patch: https://gist.github.com/833420

I recommend to fetch git branch because it's latest.

## How to use

1. Apply patch or fetch https://github.com/sorah/ruby.git parallel_test branch.
2. Build
3. Run `make TESTS='-j2' test-all
   (N of -jN is count of jobs(workers), so you can specify -j4, -j8, -j16...)
   (--jobs-status puts statuses of workers.)
   (--jobs-status=replace works same, but more beautiful;
    using some escape sequences)

## Currently to-dos

* It runs test-all completely, but some tests fail only with -jN.
* It doesn't have any tests... :(
    * Anyone can write a test?

## FAQs

Q. Why did you modify only `test/unit`?
A. minitest/unit is an outside project, and I don't think minitest can run
   multiple test.

Q. How does it work?
A. I used `spawn` because windows doesn't support fork.
   Master process (It is kicked from `make` first) spawns
   `test/unit/parallel.rb` (=worker), and master communicate via STDIN/OUT.

     master <--------------------"ready" worker
     master "run path/to/test_*.rb..."-> worker
     master <---------------------"okay" worker
     master <----"p (minitest's output)" worker
            ...
     master <----"p (minitest's output)" worker
     master <-"done (marshalled result)" worker
     master <--------------------"ready" worker
     ...loop...

Q. Doesn't work well at foobar platform
A. I welcome a patch! :)

Thanks,

-- 
Shota Fukumori a.k.a. @sora_h - http://codnote.net/