A method for testing a composite service is provided. The method may include installing a first debug probe on a first service. The method may include installing a second debug probe on a second service. The method may include executing the composite service, whereby the composite service comprises the first service and the second service. The method may include receiving a first service interaction log and a second service interaction log, whereby the first interaction log records a first plurality of I/O, and whereby the second interaction log records a second plurality of I/O. The method may include generating a global scheduling script based on the first service interaction log and the second interaction log. The method may include sending the first plurality of I/O to the first debug probe and the second plurality of I/O to the second debug probe based on the global scheduling script.