From: Nathaniel Talbott <nathaniel@...>
Date: 2004-01-09T01:11:35+09:00
Subject: Re: testunit and infinite loop

On Jan 8, 2004, at 10:49, Bil Kleb wrote:

> My searching abilities are failing me today...
>
> How does one detect an infinite loop bug with testunit?
>
> We are writing code test-first and we have found a test which causes
> an (erroneous) infinite loop, but we do not know how to write an
> *automated* test to expose it -- i.e., we do not have the luxury
> of using ctrl-c when this piece of testing code gets inserted into
> our build/test robot.
>
> We have been considering the following hack:
>
> a) spawn two threads, one calling the code with the infinite
>    loop bug and another that merely sleeps for a period of
>    time much longer that the first task should ever take if
>    the bug weren't there.
>
> b) raise an exception if the sleeping thread returns before
>    the other one.

Could you just use timeout?

   require 'test/unit'
   require 'timeout'

   class TC < Test::Unit::TestCase
     def test_it
       assert_nothing_raised do
         timeout(5) do
           loop{sleep(1)}
         end
       end
     end
   end

   ntalbott@jacob:~/sandbox$ ruby t.rb
   Loaded suite t
   Started
   F
   Finished in 5.186834 seconds.

     1) Failure:
   test_it(TC) [t.rb:10]:
   Exception raised:
   Class: <Timeout::Error>
   Message: <"execution expired">
   ---Backtrace---
   /usr/local/lib/ruby/1.9/timeout.rb:42:in `test_it'
   t.rb:8:in `loop'
   t.rb:8:in `test_it'
   t.rb:7:in `timeout'
   /usr/local/lib/ruby/1.9/timeout.rb:55:in `timeout'
   t.rb:7:in `test_it'
   t.rb:6:in `assert_nothing_raised'
   t.rb:10:in `test_it'
   ---------------

   1 tests, 1 assertions, 1 failures, 0 errors

Please let me know if I'm misunderstanding your question.

HTH,


Nathaniel

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