I think you need a pointer to QObject:
connect(foo, SIGNAL(somethingChanged()), &loop, SLOT(quit()));
edit: the error message complains about types that are not visibile from your sample:
error: no matching function for call to 'TestObjectHere::connect(objectTest&, const char*, QEventLoop&, const char*)'
also objectTest& should be changed to a pointer, instead of a reference. In the code posted, foo is a pointer, then you should have a mismatch between actual code passed to compiler and what you show.
Try to act similarly on source, for instance, prepend the pointer to operator, as we have done for target.