Add actions tests using snapshots

Ghost User
2018-03-10T12:20:52+01:00

Because `toEqual` is for peasants.

![coverage report](https://gitlab.science.ru.nl/thalia/ThaliApp/badges/master/coverage.svg) -> ![coverage report](https://gitlab.science.ru.nl/thalia/ThaliApp/badges/feature/action-tests/coverage.svg)