[bug:trunk] "./ruby test/runner.rb -j 2 test/digest" doesn't work

$B0J2<$N$h$&$K!"(B./ruby test/runner.rb -j 2 test/digest $B$H$9$k$H!"(B
$B%F%9%H$N%U%!%$%k$r8+$D$1$i$l$J$$$h$&$G$9!#(B

% ./ruby test/runner.rb -j 2 test/digest
Run options: -j 2

Running tests:

Retrying…

test/digest/test_digest.rb: cannot load such file –
test/digest/test_digest.rb (LoadError)
test/digest/test_digest_hmac.rb: cannot load such file –
test/digest/test_digest_hmac.rb (LoadError)
test/digest/test_digest_extend.rb: cannot load such file –
test/digest/test_digest_extend.rb (LoadError)

Finished tests in 0.986568s, 0.0000 tests/s, 0.0000 assertions/s.

0 tests, 0 assertions, 0 failures, 0 errors, 0 skips

ruby -v: ruby 2.0.0dev (2011-11-01 trunk 33603) [x86_64-linux]

$B0J2<$N$h$&$K!"(B-j $B$r;XDj$7$J$1$l$PLdBj$J$/F0$-$^$9!#(B

% ./ruby test/runner.rb test/digest
Run options:

Running tests:

Finished tests in 0.063393s, 1293.5130 tests/s, 4432.6482 assertions/s.

82 tests, 281 assertions, 0 failures, 0 errors, 0 skips

ruby -v: ruby 2.0.0dev (2011-11-01 trunk 33603) [x86_64-linux]