title: random number generator test
body: <p>How will you test if the random number generator is generating actual random numbers?</p>
  
  <p>My Approach: Firstly build a hash of size M, where M is the prime number. Then take the number
               generated by random number generator, and take mod with M.
               and see it fills in all the hash or just in some part.
               That's my approach. Can we prove it with visualization?</p>
  
  <p>Since I have very less knowledge about testing. Can you suggest me a thorough approach of this question? Thanks in advance</p>