'If the wrapped method returns a value on the first call, the value is
returned and no retries are made.'

def test_success(self):

    time = []
    sleep = time.append
    expected = object()
    another = object()
    results = [another, expected]
    wrapper = with_retry(results.pop, sleep=sleep)
    actual = wrapper()
    self.expectThat(actual, Equals(expected))
    self.expectThat(results, Equals([another]))
