tst_WebGL failed on linux

agent:2018/11/10 09:37:32 build.go:193: /home/qt/work/qt/qtwebglplugin/tests/plugins/platforms/webgl/target_wrapper.sh  ./tst_webgl -o /home/qt/work/testresults/tests/plugins/platforms/webgl402954174,xml -o -,txt
agent:2018/11/10 09:37:32 build.go:193: ********* Start testing of tst_WebGL *********
agent:2018/11/10 09:37:32 build.go:193: Config: Using QtTest library 5.12.0, Qt 5.12.0 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 8.2.0)
agent:2018/11/10 09:37:32 build.go:193: PASS   : tst_WebGL::initTestCase()
agent:2018/11/10 09:37:32 build.go:193: QDEBUG : tst_WebGL::checkFunctionCount(Basic scene) 2184 "QSGThreadedRenderLoop: expose event received for window QQuickView(0x14c80f0 exposed, visibility=QWindow::Windowed, flags=QFlags<Qt::WindowType>(Window|WindowTitleHint|WindowSystemMenuHint|WindowMinMaxButtonsHint|WindowCloseButtonHint|WindowFullscreenButtonHint), title=qmlscene, geometry=0,0 0x0) with invalid geometry: QRect(0,0 0x0) on QScreen(0x1462ca0, name=)\n"
agent:2018/11/10 09:37:32 build.go:193: QDEBUG : tst_WebGL::checkFunctionCount(Basic scene) 2184 "ASSERT: \"ctx\" in file /home/qt/work/qt/qtdeclarative/src/quick/items/qquickopenglshadereffectnode.cpp, line 369\n"
agent:2018/11/10 09:37:48 build.go:193: FAIL!  : tst_WebGL::checkFunctionCount(Basic scene) '(tryToConnect())' returned FALSE. ()
agent:2018/11/10 09:37:48 build.go:193:    Loc: [tst_webgl.cpp(438)]
agent:2018/11/10 09:37:48 build.go:193: QDEBUG : tst_WebGL::waitForSwapBuffers(Basic scene) 2189 "QSGThreadedRenderLoop: expose event received for window QQuickView(0x561630 exposed, visibility=QWindow::Windowed, flags=QFlags<Qt::WindowType>(Window|WindowTitleHint|WindowSystemMenuHint|WindowMinMaxButtonsHint|WindowCloseButtonHint|WindowFullscreenButtonHint), title=qmlscene, geometry=0,0 0x0) with invalid geometry: QRect(0,0 0x0) on QScreen(0x519c00, name=)\n"
agent:2018/11/10 09:37:48 build.go:193: QDEBUG : tst_WebGL::waitForSwapBuffers(Basic scene) 2189 "ASSERT: \"ctx\" in file /home/qt/work/qt/qtdeclarative/src/quick/items/qquickopenglshadereffectnode.cpp, line 369\n"
agent:2018/11/10 09:37:48 build.go:193: FAIL!  : tst_WebGL::waitForSwapBuffers(Basic scene) 'portString.size()' returned FALSE. ()
agent:2018/11/10 09:37:48 build.go:193:    Loc: [tst_webgl.cpp(445)]
agent:2018/11/10 09:37:48 build.go:193: QDEBUG : tst_WebGL::reload(Basic scene) 2195 "QSGThreadedRenderLoop: expose event received for window QQuickView(0x4f1040 exposed, visibility=QWindow::Windowed, flags=QFlags<Qt::WindowType>(Window|WindowTitleHint|WindowSystemMenuHint|WindowMinMaxButtonsHint|WindowCloseButtonHint|WindowFullscreenButtonHint), title=qmlscene, geometry=0,0 0x0) with invalid geometry: QRect(0,0 0x0) on QScreen(0x4a9690, name=)\n"
agent:2018/11/10 09:37:48 build.go:193: QDEBUG : tst_WebGL::reload(Basic scene) 2195 "ASSERT: \"ctx\" in file /home/qt/work/qt/qtdeclarative/src/quick/items/qquickopenglshadereffectnode.cpp, line 369\n"
agent:2018/11/10 09:38:03 build.go:193: FAIL!  : tst_WebGL::reload(Basic scene) '(tryToConnect())' returned FALSE. ()
agent:2018/11/10 09:38:03 build.go:193:    Loc: [tst_webgl.cpp(438)]
agent:2018/11/10 09:38:03 build.go:193: QDEBUG : tst_WebGL::reload(Colors) 2227 "QSGThreadedRenderLoop: expose event received for window QQuickView(0x5f13c0 exposed, visibility=QWindow::Windowed, flags=QFlags<Qt::WindowType>(Window|WindowTitleHint|WindowSystemMenuHint|WindowMinMaxButtonsHint|WindowCloseButtonHint|WindowFullscreenButtonHint), title=qmlscene, geometry=0,0 0x0) with invalid geometry: QRect(0,0 0x0) on QScreen(0x5d5690, name=)\n"
agent:2018/11/10 09:38:03 build.go:193: QDEBUG : tst_WebGL::reload(Colors) 2227 "ASSERT: \"ctx\" in file /home/qt/work/qt/qtdeclarative/src/quick/items/qquickopenglshadereffectnode.cpp, line 369\n"
agent:2018/11/10 09:38:03 build.go:193: FAIL!  : tst_WebGL::reload(Colors) 'portString.size()' returned FALSE. ()
agent:2018/11/10 09:38:03 build.go:193:    Loc: [tst_webgl.cpp(445)]
agent:2018/11/10 09:38:03 build.go:193: QDEBUG : tst_WebGL::update(Colors) 2232 "QSGThreadedRenderLoop: expose event received for window QQuickView(0x210b8c0 exposed, visibility=QWindow::Windowed, flags=QFlags<Qt::WindowType>(Window|WindowTitleHint|WindowSystemMenuHint|WindowMinMaxButtonsHint|WindowCloseButtonHint|WindowFullscreenButtonHint), title=qmlscene, geometry=0,0 0x0) with invalid geometry: QRect(0,0 0x0) on QScreen(0x20c4370, name=)\n"
agent:2018/11/10 09:38:03 build.go:193: QDEBUG : tst_WebGL::update(Colors) 2232 "ASSERT: \"ctx\" in file /home/qt/work/qt/qtdeclarative/src/quick/items/qquickopenglshadereffectnode.cpp, line 369\n"
agent:2018/11/10 09:38:03 build.go:193: FAIL!  : tst_WebGL::update(Colors) 'portString.size()' returned FALSE. ()
agent:2018/11/10 09:38:03 build.go:193:    Loc: [tst_webgl.cpp(445)]
agent:2018/11/10 09:38:03 build.go:193: QDEBUG : tst_WebGL::update(Launcher) 2237 "ASSERT: \"ctx\" in file /home/qt/work/qt/qtdeclarative/src/quick/items/qquickopenglshadereffectnode.cpp, line 369\n"
agent:2018/11/10 09:38:03 build.go:193: FAIL!  : tst_WebGL::update(Launcher) 'portString.size()' returned FALSE. ()
agent:2018/11/10 09:38:03 build.go:193:    Loc: [tst_webgl.cpp(445)]
agent:2018/11/10 09:38:03 build.go:193: PASS   : tst_WebGL::cleanupTestCase()
agent:2018/11/10 09:38:03 build.go:193: Totals: 2 passed, 6 failed, 0 skipped, 0 blacklisted, 31273ms
agent:2018/11/10 09:38:03 build.go:193: ********* Finished testing of tst_WebGL *********
agent:2018/11/10 09:38:03 build.go:193: Makefile:321: recipe for target 'check' failed
agent:2018/11/10 09:38:03 build.go:193: make: *** [check] Error 6