Showing papers by "James A. Jones published in 2008"

An empirical study of the effects of test-suite reduction on fault localization

Abstract: Fault-localization techniques that utilize information about all test cases in a test suite have been presented. These techniques use various approaches to identify the likely faulty part(s) of a program, based on information about the execution of the program with the test suite. Researchers have begun to investigate the impact that the composition of the test suite has on the effectiveness of these fault-localization techniques. In this paper, we present the first experiment on one aspect of test-suite composition--test-suite reduction. Our experiment studies the impact of the test-suite reduction on the effectiveness of fault-localization techniques. In our experiment, we apply 10 test-suite reduction strategies to test suites for eight subject programs. We then measure the differences between the effectiveness of four existing fault-localization techniques on the unreduced and reduced test suites. We also measure the reduction in test-suite size of the 10 test-suite reduction strategies. Our experiment shows that fault-localization effectiveness varies depending on the test-suite reduction strategy used, and it demonstrates the trade-offs between test-suite reduction and fault-localization effectiveness.

Rapid: Identifying Bug Signatures to Support Debugging Activities

Abstract: Most existing fault-localization techniques focus on identifying and reporting single statements that may contain a fault. Even in cases where a fault involves a single statement, it is generally hard to understand the fault by looking at that statement in isolation. Faults typically manifest themselves in a specific context, and knowing that context is necessary to diagnose and correct the fault. In this paper, we present a novel fault-localization technique that identifies sequences of statements that lead to a failure. The technique works by analyzing partial execution traces corresponding to failing executions and identifying common segments in these traces, incrementally. Our approach provides developers a context that is likely to result in a more directed approach to fault understanding and a lower overall cost for debugging.

Semi-automatic fault localization

Abstract: One of the most expensive and time-consuming components of the debugging process is locating the errors or faults. To locate faults, developers must identify statements involved in failures and select suspicious statements that might contain faults. In practice, this localization is done by developers in a tedious and manual way, using only a single execution, targeting only one fault, and having a limited perspective into a large search space. The thesis of this research is that fault localization can be partially automated with the use of commonly available dynamic information gathered from test-case executions in a way that is effective, efficient, tolerant of test cases that pass but also execute the fault, and scalable to large programs that potentially contain multiple faults. The overall goal of this research is to develop effective and efficient fault localization techniques that scale to programs of large size and with multiple faults. There are three principle steps performed to reach this goal: (1) Develop practical techniques for locating suspicious regions in a program; (2) Develop techniques to partition test suites into smaller, specialized test suites to target specific faults; and (3) Evaluate the usefulness and cost of these techniques. In this dissertation, the difficulties and limitations of previous work in the area of fault-localization are investigated. These investigations informed the development of a new technique, called Tarantula, that addresses some key limitations of prior work in the area, namely effectiveness, efficiency, and practicality. Empirical evaluation of the Tarantula technique shows that it is efficient and effective for many faults. The evaluation also demonstrates that the Tarantula technique can loose effectiveness as the number of faults increases. To address the loss of effectiveness for programs with multiple faults, supporting techniques have been developed and are presented. The empirical evaluation of these supporting techniques demonstrates that they can enable effective fault localization in the presence of multiple faults. A new mode of debugging, called parallel debugging, is developed and empirical evidence demonstrates that it can provide a savings in terms of both total expense and time to delivery. A prototype visualization is provided to display the fault-localization results as well as to provide a method to interact and explore those results. Lastly, a study on the effects of the composition of test suites on fault-localization is presented.