Given an integer array of size n, find any three numbers
Return any three descending numbers that appear sequentially in the input such that A[i] > A[j] > A[k] and i &lt; j &lt; k. 
  Since problem description contains 'any', I could not unit test using junits.


I think you could create inputs for tests where 


there is only one of this sequence and check that,
there are only a couple of possible sequences and check that the returned one whether exists in the possible return values list or not,
there isn't any valid sequence.