Mocks made no sense here. Also introduced a "new" way of naming test
functions. Output now looks as follows:
s\Icinga\Web\Hook
[x] Knows which hooks are registered
[x] Correctly handles multiple instances
[x] Returns null for invalid hooks
[x] Returns null for failing hook
[x] Checks whether created instances inherit base classes
[x] Throws errors for instances not inheriting base classes
[x] Creates identical instances only once
[x] Returns an empty array with no registered hook
3a5415f7c8