import pytest
from util.failover import failover, FailoverException
class Counter(object):
""" Wraps a counter in an object so that it'll be passed by reference. """
def __init__(self):
self.calls = 0
def increment(self):
self.calls += 1
@failover
def my_failover_func(i, should_raise=None):
""" Increments a counter and raises an exception when told. """
i.increment()
if should_raise is not None:
raise should_raise()
raise FailoverException(None, 'incrementing')
@pytest.mark.parametrize('stop_on,exception', [
(10, None),
(5, IndexError),
])
def test_readonly_failover(stop_on, exception):
""" Generates failover arguments and checks against a counter to ensure that
the failover function has been called the proper amount of times and stops
at unhandled exceptions.
"""
counter = Counter()
arg_sets = []
for i in xrange(stop_on):
should_raise = exception if exception is not None and i == stop_on-1 else None
arg_sets.append(((counter,), {'should_raise': should_raise}))
if exception is not None:
with pytest.raises(exception):
my_failover_func(*arg_sets)
else:
assert counter.calls == stop_on
