Just call for clearance/taxi/whatever - you'll soon find out/be told if your radio isn't working.
Quite so! All this 'radio check' stuff is a waste of time in little spamcans.
As for those self-appointed street-rapper DJs masquerading as ATCOs in the States, they should remember the maxim "Speak fast, speak twice!" - come out with a rapid fire string of instructions and you'll only have to repeat them!