Do not trust irb exit status
Notice this strange behavior with exit status and irb. The $? variable holds the exit status of the last command.
In plain ruby, everything works as expected:
% ruby -e "exit 4" % echo $? 4
However, in irb, the exit status is 0:
% irb irb(main):001:0> exit 4 % echo $? 0
It seems like irb ignores the exit status and always returns 0 (success). This introduces strange behavior around running tests. Test::Unit tests are run when the ruby process exits, and the exit status is non-zero if there were test failures. However, if the tests are run from irb, the exit status is 0 with failing tests.
In plain ruby:
% ruby failing_test.rb Loaded suite failing_test Started E Finished in 0.001127 seconds. 1) Error: test_fail(FailingTest): RuntimeError: failing_test.rb:5:in `test_fail' 1 tests, 0 assertions, 0 failures, 1 errors % echo $? 1
% irb >> require 'failing_test' => true >> exit Loaded suite irb Started E Finished in 0.00077 seconds. 1) Error: test_fail(FailingTest): RuntimeError: ./failing_test.rb:5:in `test_fail' 1 tests, 0 assertions, 0 failures, 1 errors /usr/lib/ruby/1.8/irb.rb:76:in `throw': uncaught throw `IRB_EXIT' (NameError) from /usr/lib/ruby/1.8/irb.rb:76:in `irb_exit' from /usr/lib/ruby/1.8/irb/context.rb:226:in `exit' from /usr/lib/ruby/1.8/irb/extend-command.rb:24:in `exit' from /usr/lib/ruby/1.8/test/unit.rb:278 from /usr/bin/irb:13 % echo $? 0