qmltest::item-grabber() failed on OS X 10.11

~/qt/qt5-build/qtdeclarative/tests/auto/qmltest$ make check
/Users/liangqi/qt/qt5-build/qtdeclarative/tests/auto/qmltest/target_wrapper.sh  ./tst_qmltest 
********* Start testing of qmltest *********
Config: Using QtTest library 5.6.1, Qt 5.6.1 (x86_64-little_endian-lp64 shared (dynamic) debug build; by Clang 7.3.0 (clang-703.0.31) (Apple))
...
QWARN  : qmltest::UnknownTestFunc() file:///Users/liangqi/qt/qt5/qtdeclarative/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml:103:5: QML Image: Cannot open: file:///Users/liangqi/qt/qt5/qtdeclarative/tests/auto/qmltest/itemgrabber/image.png
QWARN  : qmltest::UnknownTestFunc() file:///Users/liangqi/qt/qt5/qtdeclarative/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml:118:5: QML Image: Cannot open: file:///Users/liangqi/qt/qt5/qtdeclarative/tests/auto/qmltest/itemgrabber/image_small.png
PASS   : qmltest::item-grabber::initTestCase()
FAIL!  : qmltest::item-grabber::test_endresult() Compared values are not the same
   Actual   (): 0
   Expected (): 100
   Loc: [/Users/liangqi/qt/qt5/qtdeclarative/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml(50)]
PASS   : qmltest::item-grabber::cleanupTestCase()
...
********* Finished testing of qmltest *********