When testing a background process that streams significant amounts of data to $stdout the test eventually blocks on a write to $stdout and the test process halts indefinitely. This problem is a result of the switch to the background_process gem to implement the run command. An issue respecting this matter has been raised with the gem author

http://github.com/timcharper/background_process/issues#issue/2

but no response has been forthcoming.

Attempts to work around this matter by manually flushing $stdout in the test process itself has no effect on the behaviour of the test. Initially I thought that this was strictly a Ruby-1.9.2 problem as all tests passed when run under 1.8.7. However, by slightly increasing the amount of data sent to $stdout the problem also arises in Ruby-1.8.7.

While this is, strictly speaking, a problem with the background_process gem itself, its presence makes the use of it in aruba somewhat problematic.