def test_lazy_load_doesnt_load_data_on_subsequent_calls(mocker):
load_stations = mocker.patch('herdcats.tube._load_stations')
load_connections = mocker.patch('herdcats.tube._load_connections')
mocker.patch('herdcats.tube.STATIONS', {})
mocker.patch('herdcats.tube.CONNECTIONS', {})
func = mocker.Mock()
decorated_func = tube._lazy_load_data(func)
decorated_func()
load_stations.assert_not_called()
load_connections.assert_not_called()
def test_lazy_load_loads_data_on_first_call(mocker):
mocker.patch('herdcats.tube.STATIONS', None)
mocker.patch('herdcats.tube.CONNECTIONS', None)
load_stations = mocker.patch('herdcats.tube._load_stations')
load_connections = mocker.patch('herdcats.tube._load_connections')
func = mocker.Mock()
decorated_func = tube._lazy_load_data(func)
decorated_func()
load_stations.assert_called_once_with()
load_connections.assert_called_once_with()