There are very few things you can do wrong with a cable.
If the insulation is bad, you can see it when building it in.
If the conductive inner wire has high resistance, the voltage drops. That can be measured by a multimeter.
Or the connector can have fitting problems, being loose or too hard to fit. Those you must have noticed by installation as well.
Even if the cable is cheap, there is no other cause for alarm. If you want to be sure, just check the voltage