qsoundeffect test fails on linux with pulseaudio backend

Running this test over and over produces failures like:
PASS : tst_QSoundEffect::testDestroyWhileRestartPlaying()
QFATAL : tst_QSoundEffect::testSetSourceWhileLoading() ASSERT: "state() == Ready" in file /home/korbatit/depot/qt5/qtmultimedia/src/multimedia/audio/qsamplecache_p.h, line 94
FAIL! : tst_QSoundEffect::testSetSourceWhileLoading() Received a fatal error.

QSample::format() will assert if state not equal to Ready.
Added in a QCoreApplication::processEvents() and this issue was resolved but replaced with a failure somewhere else.

The two threads seem to be getting out of sync.