Created attachment 147472 [details] An example of test result The test case "inspector/debugger/xhr-breakpoints.html" failed due to timeout. The test result shows "FAIL: Timed out waiting for notifyDone to be called". There are three test suite in it, usually only one or two test suites can pass the test depending on the test environment. At least in Qt Browser, after I assigned a larger value to "m_timeout" of "Tools/DumpRenderTree/qt/LayoutTestControllerQt.cpp", things are improved. Or if we split it into three cases according the three test suites of it, every small case can pass the test.