Multimeter test wires without zzzZZZZ

I am installing led ballast bypass bulbs in my kitchen flourescent fixture. I think the installation instructions make sense and I'm pretty sure of the breaker to turn off. My question is how to test the wires with a multimeter after I turn off the breaker but before I remove the wire connectors. Otherwise, how do I remove the wire connectors without shocking myself if I didn't flip off the right breaker in order to test?

Thanks!!!