'The L{Deferred} returned by L{getProcessOutput} is fired with an
L{IOError} L{Failure} if the child process writes to stderr.'

def test_outputWithErrorIgnored(self):

    scriptFile = self.makeSourceFile(['import    sys', 'sys.stderr.write("hello    world\\n")'])
    d = utils.getProcessOutput(self.exe, ['-u', scriptFile])
    d = self.assertFailure(d, IOError)
    def cbFailed(err):
        return self.assertFailure(err.processEnded, error.ProcessDone)
    d.addCallback(cbFailed)
    return d
