Software testing involving users is always a challenge. The combination of the Learnability Testing particularities and the behavioral characteristics of Down Syndrome children makes this challenge especially difficult, since may promote in users negative behaviors such as lack of motivation, fear, shame, boredom and angry. In this paper we present a Learnability study applied over a population of Down Syndrome children, based in two peerworking techniques: Co-discovery and Peer-tutoring. Cooperative learnability is the combination of such techniques in a unique process, it allowed us to improve the emotional-environment during tests, providing a more relaxing, participating, and engaging testing experience. Results showed that certain barriers experienced during the application of previous Learnability studies, over the same population, were overcome by implementing peerworking techniques.