Test system with multi tester can perform conformance test for multi port protocol, among which synchronization problems are encountered. External synchronization links between testers of ports are added and synchronization operations are added to test sequence to solve this problem. The finite state machine (FSM) model is commonly used for specifying communication protocols and other types of distributed systems. A synchronous test sequence of an FSM is a test sequence for which the synchronization problem either does not exist or can be solved by communication between testers. Previous works on synchronous test sequences of an FSM bring forward several types of synchronization problem including pair synchronization test problem, multi port synchronization test problem, and tight synchronization test problem. In this paper, two synchronization test problems are considered for an FSM: port based testing, which does not allow testers for the FSM to communicate with each other, and group based testing, which divides ports of the FSM into mutually disjoint groups and allows testers for ports in the same group to communicate with each other. This paper proposes a new synchronous test sequence generation method based on synchronous digraph, which is suitable for pair, port and group synchronization problem. A method to judge how to add external synchronization operations in a nonsynchronous test sequence to change it to synchronous one is also proposed.

Protocol test is an important phase of protocol engineering.In this paper,first,a new method of generation of communication protocol test sequence is proposed.The method uses formal description technique based on constructed type algebra to describle specification of protocol and generates test sequence from the description of the specification.Secondly,the paper introduces this method with an example of describing part of the specification of stack and the test sequence is also generated.Thirdly,test sequence of stack is also generatied based on finite state machine(FSM) and the compare of the two method is put forward.Finially,conclusion is given that in some aspects,the two methods are equivalent,but the former one is better when deal with large state space.

The finite state machine (FSM) model is commonly used for specifying communication protocols and other types of distributed systems. For an FSM with multiple ports, multiple testers are needed. Testing whether a multi-party protocol implementation conforms to the specification can be achieved by a testing system with K testers (where K≥2), among which synchronization problems are encountered. A synchronizble test sequence of an FSM is a test sequence for which the synchroniztion problem does not exist. Now external synchronization operations are added to test sequence to solve this problem. For each type of testing, a necessary and sufficient condition is defined, under which a test sequence of an FSM is synchronizable. In this paper a new model—synchroniable digraph is proposed, which can judge whether there exist any synchronizable test sequence for a given specification without synchronization operation, and which can transform its nonsynchronizable test sequence to synchronizable test sequence if the answer is true. A method to judge how to add external synchronization operations in a nonsynchronizable test sequence to change it to synchroniable one is also proposed.

The finite state machine (FSM) model is commonly used for specifying communication protocols and other types of distributed systems. For an FSM with multiple ports, multiple testers are needed. Testing whether a multi-party protocol implementation conforms to the specification can be achieved by a testing system with K testers (where K≥2), among which synchronization problems are encountered. A synchronizble test sequence of an FSM is a test sequence for which the synchroniztion problem does not exist. Now external synchronization operations are added to test sequence to solve this problem. For each type of testing, a necessary and sufficient condition is defined, under which a test sequence of an FSM is synchronizable. In this paper a new model - synchroniable digraph is proposed, which can judge whether there exist any synchronizable test sequence for a given specification without synchronization operation, and which can transform its nonsynchronizable test sequence to synchronizable test sequence i f the answer is true. A method to judge how to add external synchronization operations in a nonsynchronizable test sequence to change it to synchroniable one is also proposed.