Test run crashes on long qWait() timeout

Test runs or debugs (Ctrl-R or F5) fine however if I ran it in "Test Results" pane strange thing happen:

• one CPU core loaded up to 100%
• test crashes after few minutes on following line
   

  QTest::qWait(12 * 60 * 1000);   // Wait for 12 min

Running test in run or debug mode passes fine with no errors or crashes with CPU load near to zero. To fix the issue I set

 qputenv("QTEST_FUNCTION_TIMEOUT", "1000000");

in the test constructor. Tools -> Options -> Testing -> General : Timeout = 1000 s does  not work for some reason. However this did not fix CPU load.