Silence warnings in test code and use correct parameter when calling chained constructor

Silence warnings in test code and use correct parameter when calling chained constructor

When chaining the constructor to add a default UA, we lost one parameter (replaced it
with another). That seems wrong, so I changed it back to the (hopefully) correct one.

While we are here, suppress a few other warnings from error prone, that can't be
fixed in a quick way. Feel free, to fix them.