See: https://stackoverflow.com/questions/40016081/what-is-qmltestrunner (asked 1 year ago). This tool has been around for much longer, without a proper documentation about it.
http://doc.qt.io/qt-5/qtquick-qtquicktest.html Does not mention it at all. By looking at the source code It seems that the answer on Stack Overflow is correct:
> Is qmltestrunner part of qt quick test framework?
> Yes. [..] you need a .cpp file that contains QUICK_TEST_MAIN(xxx) and a .pro file that contains > CONFIG += qmltestcase, and build this project to run your QML unit tests. The output > binary file of this project is (almost the same as) qmltestrunner.
The "Qt Quick Test Reference Documentation" documentation should mention it and explain which is the preferred solution and why.