ACM Transactions on Software Engineering and Methodology 10 (1): 56-109 (2001)

TACCLE: a methodology for object-oriented
software Testing At the Class and Cluster LEvels

H.Y. Chen 2 , T.H. Tse 3 , and T.Y. Chen 4

[author-izer free download from ACM digital library | review by ACM Computing Reviews]


Object-oriented programming consists of several different levels of abstraction, namely the algorithmic level, class level, cluster level, and system level. The testing of object-oriented software at the algorithmic and system levels is similar to conventional programming testing. Testing at the class and cluster levels poses new challenges. Since methods and objects may interact with one another dynamically with unforeseen combinations and invocations, they are much more complex to simulate and test than the static hierarchy of functional calls in conventional programs. In this paper, we propose a methodology for object-oriented software testing at the class and cluster levels.

In class-level testing, it is essential to determine whether objects produced from the execution of implemented systems would preserve the properties defined by the specification, such as behavioral equivalence and non-equivalence. Our class-level testing methodology addresses both of these aspects. For the testing of behavioral equivalence, we propose to select fundamental pairs of equivalent ground terms as test cases using a black-box technique based on algebraic specifications, and then determine by means of a white-box technique whether the objects resulting from executing such test cases are observationally equivalent. To address the testing of behavioral non-equivalence, we have identified and analyzed several non-trivial problems in the current literature. We propose to classify term equivalence into four types, thereby setting up new concepts and deriving important properties. Based on these results, we propose an approach to deal with the problems in the generation of non-equivalent ground terms as test cases.

Relatively little research has contributed to cluster-level testing. In this paper, we also discuss black-box testing at the cluster level. We illustrate the feasibility of using Contract, a formal specification language for the behavioral dependencies and interactions among cooperating objects of different classes in a given cluster. We propose an approach to test the interactions among different classes using every individual message-passing rule in the given Contract specification. We also present an approach to examine the interactions among composite message-passing rules. We have developed four testing tools to support our methodology.

1. Huo Yan Chen is supported in part by the National Natural Science Foundation of China under Grant No. 69873020 and the Guangdong Province Science Foundation under Grants #980690 and #950618. T.H. Tse is supported in part by the Research Grants Council of Hong Kong and the University Research Committee of The University of Hong Kong. T.Y. Chen is supported in part by the Research Grants Council of Hong Kong.
2. Department of Computer Science, Jinan University. (Part of the research was performed when Chen was on leave at The University of Hong Kong.)
3. (Corresponding author.)
Department of Computer Science, The University of Hong Kong, Pokfulam, Hong Kong.
(Part of the research was performed when Tse was on leave at the Vocational Training Council, Hong Kong.)
4. Centre for Software Analysis and Testing, Swinburne University of Technology, Hawthorn 3122, Australia. (Part of the work was carried out when Chen was with the Vocational Training Council, Hong Kong.)


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