System for testing a protocol, which is active on an item of equipment, testing system including a monitor to continuously capture traces, corresponding to sequences of messages of protocol under test, a filter of the traces captured using formalized properties of the demands of protocol under test, to separate the traces into data and control parts, a temporary storage, and transfer module to transfer the filtered traces to a tester so as to emit verdicts by verifying whether the traces satisfy the demands of the formalized properties of the protocol under test, in the event of saturation of the tester leading to the emission of a notification of load, the transfer module interrupts the transfer of filtered traces to the tester and stores the traces at least partially in the temporary storage, particularly only their control parts, before resuming the transfer of filtered traces when the tester is again available.