Once the system has been developed, researchers cantest it and verify its performance (e.g., error rate, speed of authentication, energy consumption, etc.). To do so, they gather the data subjects to simulate the use of the system.
Since testing the system is one of the key activities of the research the data subjects have already provided explicit consent to the testing, and since no additional personal data are processed, the research team concludes that the risks for the rights and freedoms of the data subjects are adequately addressed and proceed with the testing.