QTest::mouseClick() not clicked on QRadioButton

auto rb1 = f->findChild<QRadioButton *>("radioButton");
QTest::mouseClick(rb1, Qt::LeftButton); 

If rb1 has not been pressed earlier, then rb1->isChecked() return false.

In the documentation for QTest::mouseClick() - The position of the click is defined by pos; the default position is the center of the widget.

If I specify cursor position manualy:

QTest::mouseClick(rb1, Qt::LeftButton, Qt::KeyboardModifiers(), QPoint(rb1->size().width()/2, rb1->size().height()/2)); 

then it's all right.