'Calling ``retry_failure`` with an empty iterator for ``steps`` is the
same as wrapping the function in ``maybeDeferred``.'

def test_no_steps(self):

    steps = []
    result = object()
    failure = Failure(ValueError('really    bad    value'))
    results = [failure, succeed(result)]
    def function():
        return results.pop(0)
    clock = Clock()
    d = retry_failure(clock, function, steps=steps)
    self.assertEqual(self.failureResultOf(d), failure)
