add more test scenarios
add more test scenarios

set buffer size as 5, first push 3 elements, and then pop 2 elements, then push 6 elements, at last pop 12 leements
zhangwei1984/adv-net-samples,twood02/adv-net-samples,zhangwei1984/adv-net-samples,gwAdvNet2015/adv-net-samples,gwAdvNet2015/adv-net-samples,twood02/adv-net-samples,gwAdvNet2015/adv-net-samples,twood02/adv-net-samples,twood02/adv-net-samples,gwAdvNet2015/adv-net-samples,zhangwei1984/adv-net-samples,gwAdvNet2015/adv-net-samples,gwAdvNet2015/adv-net-samples,twood02/adv-net-samples,zhangwei1984/adv-net-samples,twood02/adv-net-samples