That's not true. The costs would be so enormous and the benefits would be so trivial that they would not do it. Partially False India is preparing to test the Prithvi missile with a conventional warhead to its maximum range of 150 km at Pokharan. It was this activity that the US spy satellite picked up and which intelligence officials suspected as India's preparation for another nuclear test. Former AEC Chairman Homi Sethna chose not to comment.
Speculation is speculation.
All this could have more than one explanation, but the possibility that it could be preparations for a nuclear test cannot be ruled out. India is making preparation for a nuclear test, and we assume that if one nation conducts a test, the other will follow. A state could suddenly be accused of preparing to violate or break out of the CTB treaty with little or no evidence presented to support the allegation. Whether allegations of nuclear test preparations are true or not, state-parties to a CTB regime would most likely have a keen interest in determining the facts as quickly and as accurately as possible. It may be desirable to derive these facts from open source data so that the information could be collected by multiple states independently and distributed to allies and adversaries freely.