'If a signal handler is installed and siginterrupt is called with
a true value for the second argument, when that signal arrives, it
interrupts a syscall that\'s in progress.'

def test_siginterrupt_on(self):

    signal.siginterrupt(self.signum, 1)
    i = self.readpipe_interrupted()
    self.assertTrue(i)
    i = self.readpipe_interrupted()
    self.assertTrue(i)
