Nowadays, we are surrounded by system of systems, autonomous systems, interconnected systems or distributed heterogeneous systems with an increase in architecture complexity. Keeping these systems operational is a challenge as the number of potential failures which may affect their availability also increases drastically. In order to optimize availability, maintenance activities have to be designed within the design phase of the system. Whatever the implementation choice, detection, diagnostic or prevention of failures require tests. The goal for autonomous systems also pushes towards embedded detection and prevention capabilities and thus arguing and decision making between system engineers and maintenance engineers to share solutions in their respective activities. In this presentation, we talk about the ability of a system designed with Capella to be tested, including in the maintenance phase. This means to interconnect several kinds of models representing different perspectives: System Design (MBSE), RAMS Analysis (Reliability, Availability, Maintainability and Safety) and Testability. We present how a MBSE approach with Capella can be used to initiate a testability study performed with the eXpress tool from DSI International.