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try:
from unittest.mock import Mock, patch
except ImportError:
from mock import Mock, patch
from pytest import raises
from circuitbreaker import CircuitBreaker, CircuitBreakerError, circuit
class FooError(Exception):
def __init__(self, val=None):
self.val = val
class BarError(Exception):
pass
def test_circuitbreaker__str__():
cb = CircuitBreaker(name='Foobar')
assert str(cb) == 'Foobar'
def test_circuitbreaker_error__str__():
cb = CircuitBreaker(name='Foobar')
cb._last_failure = Exception()
error = CircuitBreakerError(cb)
assert str(error).startswith('Circuit "Foobar" OPEN until ')
assert str(error).endswith('(0 failures, 30 sec remaining) (last_failure: Exception())')
def test_circuitbreaker_should_save_last_exception_on_failure_call():
cb = CircuitBreaker(name='Foobar')
func = Mock(side_effect=IOError)
with raises(IOError):
cb.call(func)
assert isinstance(cb.last_failure, IOError)
def test_circuitbreaker_should_clear_last_exception_on_success_call():
cb = CircuitBreaker(name='Foobar')
cb._last_failure = IOError()
assert isinstance(cb.last_failure, IOError)
cb.call(lambda: True)
assert cb.last_failure is None
def test_circuitbreaker_should_call_fallback_function_if_open():
fallback = Mock(return_value=True)
func = Mock(return_value=False, __name__="Mock") # attribute __name__ required for 2.7 compat with functools.wraps
CircuitBreaker.opened = lambda self: True
cb = CircuitBreaker(name='WithFallback', fallback_function=fallback)
decorated_func = cb.decorate(func)
decorated_func()
fallback.assert_called_once_with()
def test_circuitbreaker_should_not_call_function_if_open():
fallback = Mock(return_value=True)
func = Mock(return_value=False, __name__="Mock") # attribute __name__ required for 2.7 compat with functools.wraps
CircuitBreaker.opened = lambda self: True
cb = CircuitBreaker(name='WithFallback', fallback_function=fallback)
decorated_func = cb.decorate(func)
assert decorated_func() == fallback.return_value
assert not func.called
def mocked_function(*args, **kwargs):
pass
def test_circuitbreaker_call_fallback_function_with_parameters():
fallback = Mock(return_value=True)
cb = circuit(name='with_fallback', fallback_function=fallback)
# mock opened prop to see if fallback is called with correct parameters.
cb.opened = lambda self: True
func_decorated = cb.decorate(mocked_function)
func_decorated('test2', test='test')
# check args and kwargs are getting correctly to fallback function
fallback.assert_called_once_with('test2', test='test')
@patch('circuitbreaker.CircuitBreaker.decorate')
def test_circuit_decorator_without_args(circuitbreaker_mock):
def function():
return True
circuit(function)
circuitbreaker_mock.assert_called_once_with(function)
def test_circuit_decorator_with_args():
def function_fallback():
return True
breaker = circuit(10, 20, KeyError, 'foobar', function_fallback)
assert breaker.is_failure(KeyError, None)
assert not breaker.is_failure(Exception, None)
assert not breaker.is_failure(FooError, None)
assert breaker._failure_threshold == 10
assert breaker._recovery_timeout == 20
assert breaker._name == "foobar"
assert breaker._fallback_function == function_fallback
def test_breaker_expected_exception_is_predicate():
def is_four_foo(thrown_type, thrown_value):
return thrown_value.val == 4
breaker_four = circuit(expected_exception=is_four_foo)
assert breaker_four.is_failure(FooError, FooError(4))
assert not breaker_four.is_failure(FooError, FooError(2))
def test_breaker_default_constructor_traps_Exception():
breaker = circuit()
assert breaker.is_failure(Exception, Exception())
assert breaker.is_failure(FooError, FooError())
def test_breaker_expected_exception_is_custom_exception():
breaker = circuit(expected_exception=FooError)
assert breaker.is_failure(FooError, FooError())
assert not breaker.is_failure(Exception, Exception())
def test_breaker_constructor_expected_exception_is_exception_list():
breaker = circuit(expected_exception=(FooError, BarError))
assert breaker.is_failure(FooError, FooError())
assert breaker.is_failure(BarError, BarError())
assert not breaker.is_failure(Exception, Exception())
def test_constructor_mistake_name_bytes():
with raises(ValueError, match="expected_exception cannot be a string *"):
circuit(10, 20, b"foobar")
def test_constructor_mistake_name_unicode():
with raises(ValueError, match="expected_exception cannot be a string *"):
circuit(10, 20, u"foobar")
def test_constructor_mistake_expected_exception():
class Widget:
pass
with raises(ValueError, match="expected_exception does not look like a predicate*"):
circuit(10, 20, expected_exception=Widget)
def test_advanced_usage_circuitbreaker_subclass():
class MyCircuitBreaker(CircuitBreaker):
EXPECTED_EXCEPTION = FooError
mybreaker = circuit(cls=MyCircuitBreaker)
assert not mybreaker.is_failure(Exception, Exception())
assert mybreaker.is_failure(FooError, FooError())
def test_advanced_usage_circuitbreaker_subclass_with_list():
class MyCircuitBreaker(CircuitBreaker):
EXPECTED_EXCEPTION = (FooError, BarError)
mybreaker = circuit(cls=MyCircuitBreaker)
assert not mybreaker.is_failure(Exception, Exception())
assert mybreaker.is_failure(FooError, FooError())
assert mybreaker.is_failure(BarError, BarError())
def test_advanced_usage_circuitbreaker_subclass_with_predicate():
def is_foo_4(thrown_type, thrown_value):
return issubclass(thrown_type, FooError) and thrown_value.val == 4
class FooFourBreaker(CircuitBreaker):
EXPECTED_EXCEPTION = is_foo_4
breaker = circuit(cls=FooFourBreaker)
assert not breaker.is_failure(Exception, Exception())
assert not breaker.is_failure(FooError, FooError())
assert breaker.is_failure(FooError, FooError(4))
def test_advanced_usage_circuitbreaker_default_expected_exception():
class NervousBreaker(CircuitBreaker):
FAILURE_THRESHOLD = 1
breaker = circuit(cls=NervousBreaker)
assert breaker._failure_threshold == 1
assert breaker.is_failure(Exception, Exception())
|
