The energy transition is changing the electricity system. The growing number of energy resources distributed in the distribution network and the digitalization of most sensors and actuators are transforming the electricity grid into a Smart Grid. Component and system testing for Smart Grid topics can present many challenges. The ERIGrid project sought to understand some of the upcoming issues investigating the possibility of expanding the potential and capabilities of smart grid laboratories through the cooperation and integration of research infrastructures. ERIGrid has integrated 18 European research centers and has defined common methods, concepts and procedures for Smart Grid applications. Furthermore, through its transnational access program, ERIGrid has facilitated the free use of partner research infrastructures for researchers all over the world active in the field of Smart Grids. The project develops various tools for laboratory integration. Among these, a new methodology, called Holistic Test Description, has been developed with the aim of helping researchers clearly identify the scope of the test and the best testing procedure to adopt. Furthermore, a new communication tool, called JaNDER, has been developed by Ricerca sul Sistema Energetico (RSE), which is also a member of the ERIGrid Project consortium. This tool enables real-time data communication between research infrastructures in a simple and effective way, enabling a virtual connection between laboratories. These tools have been successfully tested and demonstrated in the RSE Distributed Energy Resources Test Facility (DER-TF) by both RSE researchers and external users, demonstrating the possibility of extending the experimental potential of Smart Grid laboratories to a large scale. The paper shows some of the tools developed and presents some tests performed in RSE DER-TF that demonstrate how laboratory integration can reduce test setup times, optimize laboratory utilization and improve the quality of testing activities.