Hi Clément and Arun, Clément, your explanation makes sense. With that information, I now understand why it isn't necessary to use make-forkexec-constructor in this case. Thank you for taking the time to explain it in detail! Arun Isaac writes: > I have finished work on the tests too. Please find attached the updated > patch. Awesome! > +(define* (run-pcscd-test) > + "Run tests of 'pcscd-service-type'." > + (define os > + (marionette-operating-system > + %pcscd-os > + #:imported-modules '((gnu services herd)))) If you use the #:requirements keyword argument to marionette-operating-system, you can guarantee that the marionette service will start up after the pcscd service. This would be good in order to avoid the possibility that you might marionette-eval something before the pcscd service is started. With that small change, if the system test passes, I think this is good to go to master. Thank you for taking the time to work on this and iterate through the feedback! -- Chris