spec 'should not touch target directory unless running'?

[Pepijn Van Eeckhoudt]

First failure I checked was this one:

it 'should not touch target directory unless running' do
    mkpath 'target' ; File.utime @early, @early, 'target'
    @filter.from('src').into('target').exclude('*').run
    File.mtime('target').should be_close(@early, 10)
end
Can this ever work? On many systems you're not allowed to set the mtime 
of a file/dir to a time in the past. The pickaxe even states that utime 
does not work on all systems. It's probably safer to read the mtime, 
sleep, run the filter and then check the mtime again. How do you do 
java.lang.Thread#sleep in ruby?

Pepijn