The test that seals it is 'getting on a crowded bus' test.
First, you have to wait in a queue, hoping no one spots you or talks to you.find the seat, sit down
Second, you have to get on and ask the driver for the ticket to where you are going, voice *is* important here.
Third, worst bit, you have to find a seat, as you turn to face the other passengers, they are all looking at you, aren't they? Feels like it.
Fourth, find the seat, sit down and hope that no one talks to you, and that when you want to get up and leave, asking someone, voice again.
In summary, once you can achieve the above with confidence then that's when you know that your transition has succeeded.
I have been transitioned for 15 years, 11 post-op and it took a long time for that level of confidence to grow to the point where I was happy with the outcome. All I can say to newer transitioners, relax, work hard on your voice, it'll get you through most tight situations. If anyone doubts your appearance, you can usually get away with it if the voice is right. It isn't necessarily the frequency, but the inflections, how you say it and what you say.
Hope that helps someone.