There to kinds of test one to see how long the battery last and two to see if the battery is good.
To see if a battery is good doesn't need a big load to see how long a battery last and is still good the user load would be a better choice.
Testing a Nicad with a 6 ohm resistor 1/2 watt would be like short not last not very long because the Nicad can dump out amps when shorted needs a 3 watt resistor.