Out of the blue DRDO is coming out with successful tests of various kind of state of the art missiles!! Recently they also tested a super sonic Interceptor missile. There are two possibilities 1)DRDO is simply testing the technology which has been already tested by others (Isreal or Russia) 2)DRDO is carrying the massive of missile development and in a very very secretive manner. They are declaring the tests to public only when they are sure about its success.
Now I think its Number 2 which is true. But DRDO should declare all the failed test after all they are the stepping stone of success, and would add to indigenous credibility.