Non required parameters with empty values are not caught

[nmeheus]

According to the specifications an empty valued parameter is not equal to the parameter not being present. For required parameters one can use the allowEmptyValue: true/false to (dis)allow ?queryparam=, but for non required query parameters there seems no way to prevent ?queryparam= and ?queryparam(*) from passing the validation.

A small snippet to illustrate the expected behaviour, and how it fails with the current implementation: https://goplay.space/#T58uhnOPA-t

(*) Note that this behaviour (without the =) is also not working as expected for required parameters.

[fenollp]

Thanks for the demo code! Amazing!

So yes there is no handling of allowEmptyValue appart from un/marshaling. PRs very welcomed!