The aim is to handover the submarine to the Indian Navy during the International Fleet Review scheduled in February next year in Vishakapatnam, they said.
"The tests held so far has been successful. We will, this month, fire Nirbhay missile from the submarine which will be followed by firing of another type of missile," the sources said.
While Nirbhay is a 1000-km-long range subsonic cruise missile, the next missile would be India's first Subamrine Launched Ballistic Missile (SLBM), which has a range of about 700 kms.
India plans to build at least two more Arihant-class submarines. India had started building Arihant in the 1990s under its highly secretive ATV (Advanced Technology Vessel) programme.
Though Arihant was initially supposed to be a fast-attack submarine, the project was realingned to make it a ballistic missile submarine following the nuclear test conducted by India in 1998.
After its launch in 2009, Arihant went through extensive tests including harbour acceptance trials with the on-board reactor going critical in 2013. It left the harbour for its sea trials in December 2014.