Several module and class testing techniques have been applied to object-oriented (OO) programs, but researchers have only recently begun developing test criteria that evaluate the use of key OO features such as inheritance, polymorphism, and encapsulation. Mutation testing is a powerful testing technique for generating software tests and evaluating the quality of software. However, the cost of mutation testing has traditionally been so high that it cannot be applied without full automated tool support. This paper presents a method to reduce the execution cost of mutation testing for OO programs by using two key technologies, mutant schemata generation (MSG) and bytecode translation. This method adapts the existing MSG method for mutants that change the program behaviour and uses bytecode translation for mutants that change the program structure. A key advantage is in performance: only two compilations are required and both the compilation and execution time for each is greatly reduced. A mutation tool based on the MSG/bytecode translation method has been built and used to measure the speedup over the separate compilation approach. Experimental results show that the MSG/bytecode translation method is about five times faster than separate compilation. Copyright © 2004 John Wiley & Sons, Ltd.

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MuJava: an automated class mutation system

Regression testing is applied to modified software to provide confidence that the changed parts behave as intended and that the unchanged parts have not been adversely affected by the modifications. To reduce the cost of regression testing, test cases are selected from the test suite that was used to test the original version of the software---this process is called regression test selection. A safe regression-test-selection algorithm selects every test case in the test suite that may reveal a fault in the modified software. Safe regression-test-selection technique that, based on the use of a suitable representation, handles the features of the Java language. Unlike other safe regression test selection techniques, the presented technique also handles incomplete programs. The technique can thus be safely applied in the (very common) case of Java software that uses external libraries of components; the analysis of the external code is note required for the technique to select test cases for such software. The paper also describes RETEST, a regression-test-selection algorithm can be effective in reducing the size of the test suite.

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Regression test selection for Java software

Although there is much interest in creating libraries of well-designed, thoroughly-tested classes that can be confidently reused for many applications, few class testing techniques have been developed. In this paper, we present a class testing technique that exploits the hierarchical nature of the inheritance relation to test related groups of classes by reusing the testing information for a parent class to guide the testing of a subclass. We initially test base classes having no parents by designing a test suite that tests each member function individually and also tests the interactions among member functions. To design a test suite for a subclass, our algorithm incrementally updates the history of its parent to reflect both the modified, inherited attributes and the subclass's newly defined attributes. Only those new attributes or affected, inherited attributes are tested and the parent class' test suites are reused, if possible, for the testing. Inherited attributes are retested in their new context in a subclass by testing their interactions with the subclass's newly defined attributes. We have incorporated a data flow tester into Free Software Foundation, Inc's C++ compiler and are using it for our experimentation.

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Incremental testing of object-oriented class structures

Regression testing is an important but expensive software maintenance activity performed with the aim of providing confidence in modified software. Regression test selection techniques reduce the cost of regression testing by selecting test cases for a modified program from a previously existing test suite. Many researchers have addressed the regression test selection problem for procedural language software, but few have addressed the problem for object-oriented software. This paper presents a regression test selection technique for use with object-oriented software. The technique constructs graph representations for software, and uses these graphs to select test cases, from the original test suite, that execute code that has been changed for the new version of the software. The technique is strictly code based, and requires no assumptions about the approach used to specify or test the software initially. The technique applies to modified and derived classes, and to application programs that use modified classes. Copyright © 2000 John Wiley & Sons, Ltd.

Regression test selection for C++ software

Research and practitioner literature on testing object-oriented software published up to the end of 1994 is summarized. The contribution of each source to eight topics presented: (1) abstract data type verification and testing as it relates to object-oriented testing; (2) testing theory—fault hypotheses for object-oriented software and adequate testing (several fault taxonomies are presented); (3) automatic model validation—techniques and tools for testing executable object-oriented representations; (4) test case design—heuristic and formal techniques to develop test cases from object-oriented representations and implementations; (5) testability—factors in controllability and observability; (6) test automation—assertions, state manipulation, comparators, object identity and built-in tests; (7) test process strategies to organize and manage the activity of testing object-oriented implementations; and (8) experience reports. Appendices provide several cross-references.

Testing object‐oriented software: a survey

A software system is a model of a problem domain in an attempt to solve the problem. Traditionally the system is constructed of units consisting of related functions-related by virtue of being constituents of a higher level function. Recently, a new approach to system decomposition has become popular. The new approach looks at the objects that make up the problem domain. Hence the name object-oriented. The data and it’s operations are collected into a unit called a class. An object is an instance of a class with its own copy of the class’ private data. In structured programming one thinks in terms of inputs, function, and outputs. In objectoriented programming (OOP) the approach is different-a message is passed to an object requesting an operation on the object. A class can inherit data and/or operations from an existing parent (or base) class. In C + + the new class is called a detived class. The inheritance feature, more than any, makes OOP a viable approach. Stroustrup [27] says, “Object-oriented programming is programming with inheritance. ”

Thomas J. Cheatham

Papers

Testing object-oriented software systems