def test_elapsed(self):
backoff = Backoff()
assert backoff.elapsed(None) == backoff.zero
now = datetime.utcnow()
sleep_delta = timedelta(0, 0, 0, 1)
sleep((sleep_delta * 2).total_seconds())
assert backoff.elapsed(now) > sleep_delta
def test_delta(self):
backoff = Backoff()
for attempt in range(backoff.max_attempts):
if attempt == 0:
assert backoff.delta(attempt) == timedelta()
continue
assert backoff.delta(attempt) == backoff.deltas[attempt]
assert backoff.delta(attempt) == timedelta(seconds=2**attempt)
# Should cap at max_attempts to highest delta
assert backoff.delta(backoff.max_attempts +
20) == timedelta(seconds=2**backoff.max_attempts)
def test_init_deltas(self):
count = 30
backoff = Backoff(count, [
timedelta(seconds=2**attempt if attempt > 0 else 0)
for attempt in range(count + 1)
])
for attempt in range(count):
if attempt == 0:
assert backoff.delta(attempt) == timedelta()
continue
assert backoff.delta(attempt) == backoff.deltas[attempt]
assert backoff.delta(attempt) == timedelta(seconds=2**attempt)
def test_init_backoff(self):
b = Backoff(10)
assert b.max_attempts == 10
q = Queue(backoff=b)
assert q.maxsize == Queue.MAX_SIZE
assert isinstance(q._backoff, Backoff)
assert q._backoff.max_attempts == 10
def test_init_backoff(self):
b = Backoff()
tracker = Tracker(b)
tracker2 = Tracker()
assert tracker.backoff == b
assert tracker2.backoff != b
assert tracker.attempts == 0
assert tracker.last_attempt is None
def test_all_attempts_edge(self):
backoff = Backoff()
assert backoff.max_attempts == Backoff.max_attempts
assert len(backoff.deltas) == 16
for edge in [-1, 0, 15, 16, 17]:
assert backoff.delta(edge) >= backoff.zero
assert backoff.remaining(edge, datetime.utcnow()) >= backoff.zero
if edge > 0:
assert backoff.expires(edge,
datetime.utcnow()) >= datetime.utcnow()
assert backoff.expired(edge, datetime.utcnow()) == False
else:
assert backoff.expires(edge,
datetime.utcnow()) <= datetime.utcnow()
assert backoff.expired(edge, datetime.utcnow())
def test_expires(self):
backoff = Backoff()
for attempt in range(backoff.max_attempts):
now = datetime.utcnow()
if attempt == 0:
assert backoff.expires(attempt, now) < datetime.utcnow()
continue
expect_delta = timedelta(seconds=2**attempt)
assert backoff.expires(attempt, now) > datetime.utcnow()
assert backoff.expires(attempt,
now - expect_delta) < datetime.utcnow()
assert backoff.expires(attempt, now -
(expect_delta * 2)) < datetime.utcnow()
assert backoff.expires(attempt,
now + expect_delta) > datetime.utcnow()
assert backoff.expires(attempt, now +
(expect_delta * 2)) > datetime.utcnow()
def test_expired(self):
backoff = Backoff()
for attempt in range(backoff.max_attempts):
now = datetime.utcnow()
if attempt == 0:
assert backoff.expired(0, now) == True
continue
expect_delta = timedelta(seconds=2**attempt)
assert backoff.expired(attempt, datetime.utcnow()) == False
assert backoff.expired(attempt,
datetime.utcnow() -
(expect_delta / 2)) == False
assert backoff.expired(attempt,
datetime.utcnow() - expect_delta) == True
assert backoff.expired(attempt,
datetime.utcnow() -
(expect_delta * 2)) == True
def test_remaining(self):
backoff = Backoff()
for attempt in range(backoff.max_attempts):
now = datetime.utcnow()
if attempt == 0:
assert backoff.remaining(attempt, now) == timedelta()
continue
expect_delta = timedelta(seconds=2**attempt)
assert backoff.remaining(attempt, now) > timedelta()
assert backoff.remaining(attempt, now) < expect_delta
assert backoff.remaining(attempt,
now - expect_delta) == timedelta()
assert backoff.remaining(attempt,
now + expect_delta) > expect_delta
def test_wait(self):
backoff = Backoff()
sleep_delta = timedelta(0, 0, 0, 5)
for attempt in range(backoff.max_attempts):
now = datetime.utcnow()
if attempt == 0:
# Wait with 0 attempts should always be instant, 500 microsec buffer
# here for when that carbon black is going hard at 100%
backoff.wait(0, now)
assert datetime.utcnow() < (now + timedelta(0, 0, 500))
continue
# Every attempt we expect a (5 millisec) sleep when calling wait
delta = timedelta(seconds=2**attempt)
last_attempt = (now - delta) + sleep_delta
expect = now - delta
backoff.wait(attempt, last_attempt)
assert datetime.utcnow() > expect
def test_expires_overflow(self):
backoff = Backoff()
assert backoff.expires(15, datetime.max) == datetime.max
assert backoff.expires(16, datetime.max) == datetime.max
def test_init_max_attempts_exceeds_deltas(self):
with pytest.raises(IndexError) as excinfo:
Backoff(2, deltas=[])
assert '`max_attempts` must not exceed the length of deltas' == str(
excinfo.value)
def test_init_max_attempts_is_zero(self):
with pytest.raises(ValueError) as excinfo:
Backoff(0)
assert '`max_attempts` must be greater than zero' == str(excinfo.value)
def test_init_max_attempts(self):
backoff = Backoff(10)
assert backoff.max_attempts == 10
assert len(backoff.deltas) == 11
def test_init(self):
backoff = Backoff()
assert backoff.max_attempts == Backoff.max_attempts
assert len(backoff.deltas) == 16
def test_str(self):
assert str(Backoff()) == 'Backoff(max_attempts={0})'.format(
Backoff.max_attempts)