Hi @Hantok,
Welcome to the community 
We can unit test our implementation contracts and create high level tests to test upgrades (https://docs.openzeppelin.com/upgrades-plugins/1.x/truffle-upgrades#test-usage)
For an example of these tests see: OpenZeppelin Upgrades: Step by Step Tutorial for Truffle
I will have to come back to you on the tests in the OpenZeppelin Contracts Upgradeable.