Refuse to do the test

Not put your seatbelt on before putting the car in gear. You don't even have to have moved the car to fail.

Fail the written portion, won't even let you take the driving portion withhout it

Take a deep swig of bourbon from your hip flask before turning on the car.

Fire a gun into the dirt as you walk out with the instructor.

Slightly related: My friend's dad, a Palestinian immigrant, got his license and t-boned a car pulling out of the DMV's lot. He got out of the car and ran away. I am not aware of him facing consequences from it, it was the 80s and he probably Arab mind-tricked anyone looking to deal with him.

Crash into the examiner’s car in the test centre car park?

Have the car not in running order (headlight out, flat tire, horn disabled, etc.)

Don't look both ways before pulling out of the parking lot into traffic. My test was over before it began.

Offer road head

I rear-ended a parked police car the first time I took the test.

Walk

Depends on how fast your car goes.

Walk to the test center?

Show up clearly drunk

Stomp on the gas and let go when they tell you that you've failed

If your need to quickly fail supercedes staying within the confines of the law, take a swing at someone working at the testing site.

The only part that will fail a driving test in Australia is failing the parking test.

Get in the back seat.