def METHOD_NAME(aggregator, mock_instance, option, url, service_check):
    # type: (AggregatorStub, dict, str, str, str) -> None
    """
    When a Prometheus endpoint is unreachable, service check reports as CRITICAL.
    """
    instance = copy.deepcopy(mock_instance)
    wrong_port = common.MOCK_SERVER_PORT + 1  # Will trigger exception.
    instance[option] = url.replace(str(common.MOCK_SERVER_PORT), str(wrong_port))
    check = AzureIoTEdgeCheck('azure_iot_edge', {}, [instance])
    with pytest.raises(requests.ConnectionError):
        check.check(instance)
    aggregator.assert_service_check(service_check, AzureIoTEdgeCheck.CRITICAL)