Where does the QA fit? Everywhere.
I get your problem: if you want the wizard to be always ready for release, you want to make sure that your work is tested before you merge for mastering. But if you do not test against the master, what if a combination of your changes and someone else causes a problem? And if both of you do, isn't there a lot of work?
IMO , . , ( ) ( ) , , .
, . , , -, , , , ( , , ), , . , - . ( , ). , , master, .
, , , - , , . , , , .
: , , . , , " , " , - , , , , ? , , , , , .