摘要 : An existing statechart testing method developed by the authors allows a tester to show the equivalence of the behaviour of an implementation of some software system to its Harel statechart specification, by testing. This requires ... 展开 An existing statechart testing method developed by the authors allows a tester to show the equivalence of the behaviour of an implementation of some software system to its Harel statechart specification, by testing. This requires a rather large test set and satisfaction of certain requirements for both a specification and an implementation. Introduction of additional constraints permits reduction in a test set size, without weakening of the conclusions obtained by testing. This paper describes how a test set can be derived from a relatively big statechart and investigates the role of a few specific constraints in the reduction of test set size, depending on where in the system structure these constraints are used. The main contribution of the paper is a demonstration that enforcing relatively weak constraints in the right place of a system's structure makes it possible to reduce the size of a test set by many orders of magnitude. The practical use of the contribution is to help developers structure a system under construction in such a way that it is completely testable using the described testing method with few additional constraints. 收起