def test_removing_host():
"""If a discovered host is failing 3 times in a row, we stop querying it."""
instance = common.generate_instance_config(common.SUPPORTED_METRIC_TYPES)
discovered_instance = instance.copy()
discovered_instance['ip_address'] = '1.1.1.1'
discovered_instance['retries'] = 0
instance.pop('ip_address')
instance['network_address'] = '192.168.0.0/24'
check = SnmpCheck('snmp', {}, [instance])
warnings = []
check.warning = warnings.append
check._config.discovered_instances['1.1.1.1'] = InstanceConfig(
discovered_instance)
msg = 'No SNMP response received before timeout for instance 1.1.1.1'
check._start_discovery = lambda: None
check._executor = futures.ThreadPoolExecutor(max_workers=1)
check.check(instance)
assert warnings == [msg]
check.check(instance)
assert warnings == [msg, msg]
check.check(instance)
assert warnings == [msg, msg, msg]
# Instance has been removed
assert check._config.discovered_instances == {}
check.check(instance)
# No new warnings produced
assert warnings == [msg, msg, msg]
