I’ll throw in my personal FTP test
I generally hate testing, so I invented my own protocol.
The Bandit Protocol.
There can never be enough protocols 
First, I personally believe this testing is best done outside. On the bike you race, with the power meter you race with. Make it valid to your actual real world performance.
Be very careful with temperature. If it’s hot, as you overheat your performance will suffer. You could use that result as your ‘heat FTP’. Essentially, what it would be at that temperature. Personally, I prefer it cool. The reduced cooling during climbing means the temperature needs to be a lot colder than many think. Best performance would be in the 13-16c degree range. Even colder on a MTB with the reduced speed.
Whatever the temp, your result is relative to that temperature. So, if you live somewhere hot, or only race in the heat. No problem. You’ll just test a little lower than you’re ultimately capable of.
Find a steady low grade hill. Your favorite one. The angle you enjoy the most. It will need to be at least 3mins of steady gradient. 4mins is better, 5mins probably optimal, although for 5mins, less fit riders will likely fatigue too rapidly.
I like 3mins myself, that’s plenty to get me where I need to be.
Wear your HR monitor, if you have one.
Take a guess at your FTP. I’m sure anybody reading this will have a pretty good idea.
Simply ride repeats. Very steady each time. I display 3sec power, 30sec power and HR. Or just do laps with average power. However, if you do use laps on your computer, remember, going 50w harder for 30sec at the end to get the target number will ruin the data. We’re interested in the power and the HR.
Warm up for a considerable time. Maybe, a full hour. Z2, bring the power up very slowly to tempo for a few minutes when you’re close to the hill. Fuel and hydrate correctly.
Simply start your first effort about 20 or 30w under what you think is your FTP is.
Ride the hill, super steady, watch your HR carefully. Take a mental note of what it peaked at. Take a very diagnostic approach. Feel your breathing, feel your pedaling technique. Keep your ideal cadence. Just nice smooth power.
Roll down the hill. No hurry at all. Relax. Take a drink, have a candy. Chill. Give it a minute or two at the bottom to rest, then go again. 10w higher power.
Repeat.
You will soon get to the point where you can feel a kind of sustainable high power. Power that you could maintain for 30-45mins, for real. It’ll likely be 10w less than your ego tells you. The repeats beyond that don’t last long. I usually do two above my FTP. The 2nd, which is 20w over it, is very obviously over it. You’ll feel it rapidly and see it in the HR response.
Pay very specific attention to the HR. Knowing your approximate threshold HR is an incredibly valuable metric.
Take your new found approximate FTP and approximate and threshold HR and experiment with training. Try some longer intervals. You’ll learn rapidly if you need to tweak it up or down a tad.
I suspect most people will get within 10w with this technique. Particularly, if you don’t let your ego have any say in the matter.
The bonus of this technique, you won’t be very tired when you’re finished. So, you can add in a nice long Z2 ride or whatever you want after completion.
I’m a small 60kg rider so 10w increments work for me. I’m also very familiar with my performance and perceived effort. It usually only takes 4 or 5 repeats to get it sorted. I know it’s not 300w and it’s not 200w. So, I’m starting at 230w, to be conservative and feeling it sits somewhere between 255w-265w.
When I do the 270w repeat, I’m starting to feel less in control, I’m certain I’ve gone past it when I do the 280w repeat.
That works for me. It’s almost fun, a billion times less painful than a ramp test and for me, vastly more accurate. For interests sake the ramp test gave me 277w . Well overestimated.
For bigger or very strong riders, it could be 20w steps. To be fair, once you’ve completed this test or have other data, a 5 repeat step covering 50w should be enough to cover every rider.
If you repeat the protocol, do it at the same time. Say, after a rest day. Same amount of caffeine, same fueling etc. Ignore Strava segment times. They are totally irrelevant. Too many variables. Don’t even look at them.
Finally, be conservative. It’ll likely be the step under the one you want it to be. Equally, it might be in between a step. Now we’re talking about 5w. I’m sorry to say that it just isn’t that accurate. Nor, does it need to be.
This is not an all out protocol, like a ramp test, you will feel like you’ve barley gone hard. This is why you’ll think it’s the step above the actual number. If it is, fantastic. You’ll find out soon enough.
Pick the honest repeat. Train off it. Adjust it.
Try it again after a training block. Hopefully, it’s up.
Enjoy 