Test definitely needs to be fixed (actually randomized) and buffed (increase number of tests).

The intended solution is devious and evil but everyone just ends up praying on RNGesus instead :P

Should be using assertEquals so it is easier to debug the tests.

Needs random test cases

1. need English description(需要英文的描述，大部分人看不懂中文)

2. need more testcases and add random testcases(需要增加测试用例，并且添加随机测试)

3. need change your test method from Test.expect to Test.assertEquals. It will give more error information to user.
   (需要改变你的测试方式，使用Test.assertEquals可以更好地回馈错误信息给用户)

4. chinese chars can not display correct in the testcases.(中文字符在测试用例中无法正常显示)