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_remaining(self):
tracker = Tracker()
for attempt in range(tracker.backoff.max_attempts):
now = datetime.utcnow()
if attempt == 0:
assert tracker.remaining() == timedelta()
continue
tracker.attempt()
expect_delta = timedelta(seconds=2**attempt)
assert tracker.remaining() > timedelta()
assert tracker.remaining() < expect_delta
tracker.last_attempt = now - expect_delta
assert tracker.remaining() == timedelta()
tracker.last_attempt = now + expect_delta
assert tracker.remaining() > expect_delta
def test_delta(self):
tracker = Tracker()
for attempt in range(tracker.backoff.max_attempts):
if attempt == 0:
assert tracker.delta() == timedelta()
continue
tracker.attempt()
assert tracker.delta() == tracker.backoff.deltas[attempt]
assert tracker.delta() == timedelta(seconds=2**attempt)
# Should cap at max_attempts to highest delta
tracker.attempts = tracker.backoff.max_attempts + 20
assert tracker.delta() == timedelta(
seconds=2**tracker.backoff.max_attempts)
def test_elapsed(self):
tracker = Tracker()
assert tracker.elapsed() == Backoff.zero
tracker.attempt()
sleep_delta = timedelta(0, 0, 0, 1)
sleep((sleep_delta * 2).total_seconds())
assert tracker.elapsed() > sleep_delta
def test_reset(self):
now = datetime.utcnow()
tracker = Tracker()
tracker.attempt()
assert tracker.attempts == 1
assert tracker.last_attempt > now
tracker.reset()
assert tracker.attempts == 0
assert tracker.last_attempt is None
def test_wait(self):
tracker = Tracker()
sleep_delta = timedelta(0, 0, 0, 5)
for attempt in range(tracker.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%
tracker.wait()
assert datetime.utcnow() < (now + timedelta(0, 0, 500))
continue
# Every attempt we expect a (5 millisec) sleep when calling wait
tracker.attempt()
delta = timedelta(seconds=2**attempt)
tracker.last_attempt = (now - delta) + sleep_delta
expect = now - delta
tracker.wait()
assert datetime.utcnow() > expect
def test_expired(self):
tracker = Tracker()
for attempt in range(tracker.backoff.max_attempts):
if attempt == 0:
assert tracker.expired() == True
continue
tracker.attempt()
expect_delta = timedelta(seconds=2**attempt)
tracker.last_attempt = datetime.utcnow()
assert tracker.expired() == False
tracker.last_attempt = datetime.utcnow() - (expect_delta / 2)
assert tracker.expired() == False
tracker.last_attempt = datetime.utcnow() - expect_delta
assert tracker.expired() == True
tracker.last_attempt = datetime.utcnow() - (expect_delta * 2)
assert tracker.expired() == True
def test_expires_overflow(self):
tracker = Tracker()
tracker.attempts = 15
tracker.last_attempt = datetime.max
assert tracker.expires() == datetime.max
def test_expires(self):
tracker = Tracker()
for attempt in range(tracker.backoff.max_attempts):
now = datetime.utcnow()
if attempt == 0:
assert tracker.expires() < datetime.utcnow()
continue
tracker.attempt()
expect_delta = timedelta(seconds=2**attempt)
assert tracker.expires() > datetime.utcnow()
tracker.last_attempt = now - expect_delta
assert tracker.expires() < datetime.utcnow()
tracker.last_attempt = now - (expect_delta * 2)
assert tracker.expires() < datetime.utcnow()
tracker.last_attempt = now + expect_delta
assert tracker.expires() > datetime.utcnow()
tracker.last_attempt = now + (expect_delta * 2)
assert tracker.expires() > datetime.utcnow()
def test_str(self):
assert str(Tracker()) == 'Tracker(attempts=0, remaining=0:00:00)'
def test_init(self):
tracker = Tracker()
assert tracker.attempts == 0
assert tracker.last_attempt is None