Is it normal for testicle to turn for 180°?

I've not heard of a testicle turning in that manner, but if it is not producing pain, there's no problem.

I know this is old but I wanted to help others who might read this. Yes, it is completely normal. The testes hang unattached to the scrotal skin and can turn and move around under certain situations (and are actually a lot easier to turn than you would think). There are usually structures that keep it from rotating completely around except in certain situations. The fact is it happens to most of us but because it is painless and often corrects itself, most just don't notice. Torsion is only a problem if the twist is completely around. Think of a hose. The water will still flow if you slightly twist it until you twist it completely around. If you are still concerned you can get a rather inexpensive ultrasound done. 

One in every 8 men lacks a gubernaculum ligament in their srcotum that holds their balls in place at the bottom of their scrotum. But only one in 4000 males ever get testicular torsion. So one in every 8 men can move his testicles in ways that other men can't do. Some men's balls can completely leave their scrotums and travel way up next to their navels and show as lumps below their stomach skin. They can push them back down into their scrotums again or they drop back down on their own when the man gets warm or has sex to pull them into ejaculation firing position. Having traveling testicles makes you more able to get testicular torsion, but it does not mean you will get it. One guy in high school would push both of his balls way up into his stomach to freak out the other guys and he had no problems having sex or making his own kids later.