func TestDevmapperCreateEmpty(t *testing.T) {
	graphtest.DriverTestCreateEmpty(t, "devicemapper")
}
func TestVfsCreateEmpty(t *testing.T) {
	graphtest.DriverTestCreateEmpty(t, "vfs")
}
func TestBtrfsCreateEmpty(t *testing.T) {
	graphtest.DriverTestCreateEmpty(t, "btrfs")
}