How to use the boltons.iterutils.backoff function in boltons

def test_backoff_zero_start():
    from boltons.iterutils import backoff

    assert backoff(0, 16) == [0.0, 1.0, 2.0, 4.0, 8.0, 16.0]
    assert backoff(0, 15) == [0.0, 1.0, 2.0, 4.0, 8.0, 15.0]

    slow_backoff = [round(x, 2) for x in backoff(0, 2.9, factor=1.2)]
    assert slow_backoff == [0.0, 1.0, 1.2, 1.44, 1.73, 2.07, 2.49, 2.9]

def test_backoff_basic():
    from boltons.iterutils import backoff

    assert backoff(1, 16) == [1.0, 2.0, 4.0, 8.0, 16.0]
    assert backoff(1, 1) == [1.0]
    assert backoff(2, 15) == [2.0, 4.0, 8.0, 15.0]

def test_backoff_jitter():
    from boltons.iterutils import backoff

    start, stop = 1, 256

    unjittered = backoff(start, stop)
    jittered = backoff(start, stop, jitter=True)

    assert len(unjittered) == len(jittered)
    assert [u >= j for u, j in zip(unjittered, jittered)]

    neg_jittered = backoff(start, stop, jitter=-0.01)

    assert len(unjittered) == len(neg_jittered)
    assert [u <= j for u, j in zip(unjittered, neg_jittered)]

    o_jittered = backoff(start, stop, jitter=-0.0)
    assert len(unjittered) == len(o_jittered)
    assert [u == j for u, j in zip(unjittered, o_jittered)]

    nonconst_jittered = backoff(stop, stop, count=5, jitter=True)
    assert len(nonconst_jittered) == 5
    # no two should be equal realistically
    assert len(set(nonconst_jittered)) == 5

def test_backoff_jitter():
    from boltons.iterutils import backoff

    start, stop = 1, 256

    unjittered = backoff(start, stop)
    jittered = backoff(start, stop, jitter=True)

    assert len(unjittered) == len(jittered)
    assert [u >= j for u, j in zip(unjittered, jittered)]

    neg_jittered = backoff(start, stop, jitter=-0.01)

    assert len(unjittered) == len(neg_jittered)
    assert [u <= j for u, j in zip(unjittered, neg_jittered)]

    o_jittered = backoff(start, stop, jitter=-0.0)
    assert len(unjittered) == len(o_jittered)
    assert [u == j for u, j in zip(unjittered, o_jittered)]

    nonconst_jittered = backoff(stop, stop, count=5, jitter=True)
    assert len(nonconst_jittered) == 5
    # no two should be equal realistically

unjittered = backoff(start, stop)
    jittered = backoff(start, stop, jitter=True)

    assert len(unjittered) == len(jittered)
    assert [u >= j for u, j in zip(unjittered, jittered)]

    neg_jittered = backoff(start, stop, jitter=-0.01)

    assert len(unjittered) == len(neg_jittered)
    assert [u <= j for u, j in zip(unjittered, neg_jittered)]

    o_jittered = backoff(start, stop, jitter=-0.0)
    assert len(unjittered) == len(o_jittered)
    assert [u == j for u, j in zip(unjittered, o_jittered)]

    nonconst_jittered = backoff(stop, stop, count=5, jitter=True)
    assert len(nonconst_jittered) == 5
    # no two should be equal realistically
    assert len(set(nonconst_jittered)) == 5

def test_backoff_zero_start():
    from boltons.iterutils import backoff

    assert backoff(0, 16) == [0.0, 1.0, 2.0, 4.0, 8.0, 16.0]
    assert backoff(0, 15) == [0.0, 1.0, 2.0, 4.0, 8.0, 15.0]

    slow_backoff = [round(x, 2) for x in backoff(0, 2.9, factor=1.2)]
    assert slow_backoff == [0.0, 1.0, 1.2, 1.44, 1.73, 2.07, 2.49, 2.9]

def test_backoff_validation():
    from boltons.iterutils import backoff

    with pytest.raises(ValueError):
        backoff(8, 2)
    with pytest.raises(ValueError):
        backoff(1, 0)
    with pytest.raises(ValueError):
        backoff(-1, 10)
    with pytest.raises(ValueError):
        backoff(2, 8, factor=0)
    with pytest.raises(ValueError):
        backoff(2, 8, jitter=20)

def test_backoff_validation():
    from boltons.iterutils import backoff

    with pytest.raises(ValueError):
        backoff(8, 2)
    with pytest.raises(ValueError):
        backoff(1, 0)
    with pytest.raises(ValueError):
        backoff(-1, 10)
    with pytest.raises(ValueError):
        backoff(2, 8, factor=0)
    with pytest.raises(ValueError):
        backoff(2, 8, jitter=20)

def test_backoff_jitter():
    from boltons.iterutils import backoff

    start, stop = 1, 256

    unjittered = backoff(start, stop)
    jittered = backoff(start, stop, jitter=True)

    assert len(unjittered) == len(jittered)
    assert [u >= j for u, j in zip(unjittered, jittered)]

    neg_jittered = backoff(start, stop, jitter=-0.01)

    assert len(unjittered) == len(neg_jittered)
    assert [u <= j for u, j in zip(unjittered, neg_jittered)]

    o_jittered = backoff(start, stop, jitter=-0.0)
    assert len(unjittered) == len(o_jittered)
    assert [u == j for u, j in zip(unjittered, o_jittered)]

    nonconst_jittered = backoff(stop, stop, count=5, jitter=True)
    assert len(nonconst_jittered) == 5

from boltons.iterutils import backoff

    start, stop = 1, 256

    unjittered = backoff(start, stop)
    jittered = backoff(start, stop, jitter=True)

    assert len(unjittered) == len(jittered)
    assert [u >= j for u, j in zip(unjittered, jittered)]

    neg_jittered = backoff(start, stop, jitter=-0.01)

    assert len(unjittered) == len(neg_jittered)
    assert [u <= j for u, j in zip(unjittered, neg_jittered)]

    o_jittered = backoff(start, stop, jitter=-0.0)
    assert len(unjittered) == len(o_jittered)
    assert [u == j for u, j in zip(unjittered, o_jittered)]

    nonconst_jittered = backoff(stop, stop, count=5, jitter=True)
    assert len(nonconst_jittered) == 5
    # no two should be equal realistically
    assert len(set(nonconst_jittered)) == 5