The implementation has to sanitize Metadata passed to registration methods
if the application does not supply the metric type explicitly, but the type is implied
by the used method.
To test the 'min' and 'max' values we have to do this:
- run invocation1 and keep it running
- wait until the next minute starts
- run invocation2 and stop it right away
- wait until the next minute starts
- stop invocation1
- after this, 'min' should be 1 and 'max' should be 2