Before qtquickcontrols2 was merged into qtdeclarative, it had a bunch of test helpers, some of which were duplicated from qtdeclarative (such as QQmlTestMessageHandler). We should try to remove any duplicates and move the qtquickcontrols2 helpers to tests/auto/shared. In the process, we can make a library out of that code, as currently there is a whole lot of unnecessary compilation going on as a result of tests including the sources rather than linking:

mitch@mitch-ubuntu-20:~/dev/qt-dev/qtdeclarative$ git grep util.h -- tests/auto/*.cpp | wc -l
270