'When given a callable that raises an exception, include a Failure for
that exception in the results list, tagged with a FAILURE flag.'

def test_singleSynchronousFailure(self):

    d = util._runSequentially([(lambda : self.fail('foo'))])
    def check(results):
        [(flag, fail)] = results
        fail.trap(self.failureException)
        self.assertEqual(fail.getErrorMessage(), 'foo')
        self.assertEqual(flag, defer.FAILURE)
    self.assertDeferredResult(d, check)
