Definition of Test Subsequence & Its Purpose
* A Test Subsequence Test(Tm; Vj, Vk; i/o) is Used to Verify the transition Tm
* To test a transition Tm=(Vj, Vk; I/o) of the FSM,
the implementation is put into state Vj,
the output is checked to see that it is o, and
the new state Vk is tested by a UIO sequence of state Vk.