Remove mocha dependency

It's a large stubbing and mocking library we hardly use. Minitest gives us all we need now without all the overhead. Plus one less dependency to watch out for. \o/

enabled an automatic merge when the pipeline for 4e7a17b5 succeeds

added 3 commits

• 6ee06433 - tests: no more mocha in functional tests
• 05c323d2 - tests: no more mocha in integration tests
• 15863717 - tests: remove mocha completely

Compare with previous version

added 4 commits

• 30acb506 - tests: do not use mocha in unit tests
• 7c73a74a - tests: no more mocha in functional tests
• 06686255 - tests: no more mocha in integration tests
• f1931686 - tests: remove mocha completely

Compare with previous version

added 1 commit

• 8b97e4c3 - minor: require_relative -> require

Compare with previous version

enabled an automatic merge when the pipeline for 8b97e4c3 succeeds

merged

mentioned in commit ae37ee53