def test_transition_events(storage):
"""It should call the appropriate functions on every state transition."""
class Listener(CircuitBreakerListener):
def __init__(self):
self.out = []
def state_change(self, breaker, old, new):
assert breaker
self.out.append((old.state, new.state))
listener = Listener()
breaker = CircuitBreaker(listeners=(listener, ), state_storage=storage)
assert CircuitBreakerState.CLOSED == breaker.current_state
breaker.open()
assert CircuitBreakerState.OPEN == breaker.current_state
breaker.half_open()
assert CircuitBreakerState.HALF_OPEN == breaker.current_state
breaker.close()
assert CircuitBreakerState.CLOSED == breaker.current_state
assert [(CircuitBreakerState.CLOSED, CircuitBreakerState.OPEN),
(CircuitBreakerState.OPEN, CircuitBreakerState.HALF_OPEN),
(CircuitBreakerState.HALF_OPEN, CircuitBreakerState.CLOSED)
] == listener.out
def test_successful_call_when_half_open(storage):
"""It should close the circuit when a call succeeds in half-open state."""
breaker = CircuitBreaker(state_storage=storage)
breaker.half_open()
assert 0 == breaker.fail_counter
assert CircuitBreakerState.HALF_OPEN == breaker.current_state
# Circuit should open
assert breaker.call(func_succeed)
assert 0 == breaker.fail_counter
assert CircuitBreakerState.CLOSED == breaker.current_state
def test_failed_call_when_half_open(storage):
"""It should open the circuit when a call fails in half-open state."""
breaker = CircuitBreaker(state_storage=storage)
breaker.half_open()
assert 0 == breaker.fail_counter
assert CircuitBreakerState.HALF_OPEN == breaker.current_state
with raises(CircuitBreakerError):
breaker.call(func_exception)
assert 1 == breaker.fail_counter
assert CircuitBreakerState.OPEN == breaker.current_state
