All condensers will read as open on an ohmmeter, whether or not they are good. An ohmmeter uses a small DC current to measure resistance, and it's the job of a condenser (capacitor) to block the flow of DC - hence, open or infinite resistance.
If a condenser reads as anything other than open, it is bad. But, if it does read open, this does not mean that it is good.
The only real way to test one is with a capacitor checker - and the old-fashioned style (that allows you to apply a high voltage) is the best type. I have an old Heathkit LCR tester for this use.