Don't forget before BJP, India burst into the nuclear club courtesy Indira Gandhi in early 70s.
The BJP succumbing to US pressure wanted to send Indian forces to Iraq. The move failed only because all other NDA allies opposed it. Still they gave US airforce rights to land for re-fuelling during the war.
The Congress is right. All nuclear powers agree that there is no need to physically test when it can be computer simulated using past test data. It was to generate such data, that the Vajpayee government continued to test bombs over sevral days. So the BJP fully this, is untruthful to the nation.