[NetteToSymfony] Nette tester to PHPunit

[TomasVotruba]

Requested at 🍺 meeting after PHP meetup at Pilulka :)

Sources

• https://github.com/nette/di/tree/master/tests

Class tests

• https://github.com/Kdyby/Doctrine/blob/master/tests/KdybyTests/Doctrine/Extension.phpt
• https://filip-prochazka.com/blog/nette-tester-a-phpstorm

Assert tests

• Assert::same( -1, foobar(0, -1) );