In Abacus, there are two Tcl API to stop a test. ::aba::ApiTest::Stop will wait for all calls are completed before stopping the test. And ::aba::ApiTest::StopNow will kill a test in the middle. What this means is that the system will not wait for the normal completion of calling, it would just stop the test as soon as it can. This could result in incomplete signaling and inconsistent call statistics. It is up to the user to choose which method best fit his application.