>>Did you try to initialize the buf array with some values for your tests?
>>
>>And also run the tests separately, not in one class?
>
>(1) Yes
>(2) What difference would that make ?

You're right - probably no difference - but just for the purity of the experiment (since in first case the array is created, may be it is somehow "re-used")?

Or try to switch the order of the tests just to exclude this potential (non-existent) problem.