QThreads never quit although emit Finished reached - c++

Question

Following scenario:
If the user press the "StartMeasure" button I start a new worker thread to avoid blocking behaviour in GUI!
There I start again n new threads for hardware communication (need parallel flow for reasons of speed) -> send/receive something and evaluate the response.
Thread model:
The problem is that the n worker threads (for HW communication) never quits!
Simplified code:
void Tool::on_btn_StartMeasure()
{
TestExecution *testExecution = new TestExecution();
QThread *workerThread = new QThread();
connect(workerThread, &QThread::started, testExecution, &TestExecution::DoTest);
connect(testExecution, &TestExecution::Finished, workerThread, &QThread::quit);
testExecution->moveToThread(workerThread);
workerThread->start();
}
TestExecution Class
class TestExecution : public QObject
{
Q_OBJECT
public:
void DoTest();
signals:
void Finished();
};
void TestExecution::DoTest()
{
std::vector<std::shared_ptr<TestFlow>> objects;
std::vector<QThreads*> workerThreads;
for(int n=0; n<numberOfDevices; n++)
{
workerThreads.push_back(new QThread());
objects.push_back(std::make_shared<TestFlow>());
connect(workerThreads.back(), &QThread::started, objects.back().get(), &TestFlow::DoWork);
connect(objects.back().get(), &TestFlow::Finished, workerThreads.back(), &QThread::quit);
objects.back()->moveToThread(workerThreads.back());
workerThreads.back()->start;
}
// wait for worker threads to finish
for(auto it=workerThreads.begin(); it!=workerThreads.end(); it++)
{
(*it)->wait(30); // wait a maximum of 30s -> for testing
}
// do something with the result <--- NEVER REACHED
emit Finished();
}
TestFlow Class
class TestFlow : public QObject
{
Q_OBJECT
public:
void DoWork();
signals:
void Finished();
};
void TestFlow::DoWork()
{
// do something
emit Finished(); <-- REACHED
}
If I reach the Finished signal in TestFlow he steps into qobject_impl.h to the method QSlotObjectBase::call(Object *r, void **a) and stops there. If I wait long enough (thread timeout of 30s) the workerThreads terminates!
Something wrong or missing here?
Thank you for any help!
UPDATE:
output of qDebug (only 1 worker thread)
Tool::on_btn_StartMeasure(), currentThread QThread(0x601b08), object thread QThread(0x601b08)
TestExecution::DoTest(), currentThread QThread(0x388bf68) , object thread QThread(0x388bf68)
TestFlow::DoWork(), currentThread QThread(0x3958690) , object thread QThread(0x3958690)
Looks ok to me?!