Karunaratne was called up into the Test squad for the home Tests against New Zealand during late 2012. He got the opportunity due to Tillakaratne Dilshan being unable to make the XI because of an injury. He debuted in the first Test of he series at Galle, only to get out for a duck in the first innings. However, he came back strongly in the second innings with an unbeaten half century as well as hitting the winning runs.[19] Following the New Zealand series, Karunaratne was called into the Test squad which was to tour Australia for a series of three Test matches. During the first two Tests, he failed to have an impact as he struggled against the Australian pace attack. In the final Test of the series held in Sydney Karunaratne managed to hit his highest test score of 85 in the second innings.