def test_ref_pyqt(): backend_ref('pyqt')
def test_ref_wx(): backend_ref('wx')
def test_ref_imagemagick(): backend_ref('imagemagick')
def test_ref_gnome_screenshot(): backend_ref('gnome-screenshot')
def test_ref_pyside(): backend_ref('pyside')
def test_ref_pygdk3(): backend_ref('pygdk3')
def test_ref_pygtk(): backend_ref('pygtk')
def test_ref_pyqt5(): backend_ref('pyqt5')