Typical documentation for object-oriented programs includes descriptions of the parameters and return types of each method in a class, but little or no information on valid method invocation sequences. Knowing the sequence with which methods of a class can be invoked is useful information especially for software engineers (e.g., developers, testers) who are actively involved in the maintenance of large software systems. This paper describes a new approach and a tool for generating class usage scenarios (i.e., how a class is used by other classes) from method invocations, which are collected during the execution of the software. Our approach is algorithmic and employs the notion of canonical sets to categorize method sequences into groups of similar sequences, where each group represents a usage scenario for a given class.

Abstract Database systems play an important role in nearly every modern organization, yet relatively little research effort has focused on how to test them. This paper discusses issues arising in testing database systems, presents an approach to testing database applications, and describes AGENDA, a set of tools to facilitate the use of this approach. In testing such applications, the state of the database before and after the user's operation plays an important role, along with the user's input and the system output. A framework for testing database applications is introduced. A complete tool set, based on this framework, has been prototyped. The components of this system are a parsing tool that gathers relevant information from the database schema and application, a tool that populates the database with meaningful data that satisfy database constraints, a tool that generates test cases for the application, a tool that checks the resulting database state after operations are performed by a database application, and a tool that assists the tester in checking the database application's output. The design and implementation of each component of the system are discussed. The prototype described here is limited to applications consisting of a single SQL query. Copyright © 2004 John Wiley & Sons, Ltd.

Database systems play an important role in nearly every modern organization, yet relatively little research effort has focused on how to test them. This paper discusses issues arising in testing database systems and presents an approach to testing database applications. In testing such applications, the state of the database before and after the user's operation plays an important role, along with the user's input and the system output. A tool for populating the database with meaningful data that satisfy database constraints has been prototyped. Its design and its role in a larger database application testing tool set are discussed.

An approach to software performance testing is discussed. A case study describing the experience of using this approach for testing the performance of a system used as a gateway in a large industrial client/server transaction processing application is presented.

Regression testing is a commonly used activity whose purpose is to determine whether the modifications made to a software system have introduced new faults. Textual differencing is a new, safe and fairly precise, selective regression testing technique that works by comparing source files from the old and the new version of the program. We have implemented the textual differencing technique in a tool called Pythia. Pythia has been developed primarily through the integration of standard, well known UNIX programs, and is capable of analyzing large software systems written in C. We present results from a case study involving a software system of approximately 11,000 lines of source code written for the European Space Agency. The results provide empirical evidence that textual differencing is very fast and capable of achieving substantial reductions in the size of the regression test suite.