Directed Test Suite Augmentation

As software evolves, engineers use regression testing to evaluate its fitness for release. Such testing typically begins with existing test cases, and many techniques have been proposed for reusing these cost-effectively. After reusing test cases, however, it is also important to consider code or behavior that has not been exercised by existing test cases and generate new test cases to validate these. This process is known as test suite augmentation. In this paper we present a directed test suite augmentation technique, that utilizes results from reuse of existing test cases together with an incremental concolic testing algorithm to augment test suites so that they are coverage-adequate for a modified program. We present results of an empirical study examining the effectiveness of our approach.

A Controlled Experiment Assessing Test Case Prioritization Techniques via Mutation Faults

Regression testing is an important part of software maintenance, but it can also be very expensive. To reduce this expense, software testers may prioritize their test cases so that those that are more important are run earlier in the regression testing process. Previous work has shown that prioritization can improve a test suite’s rate of fault detection, but the assessment of prioritization techniques has been limited to hand-seeded faults, primarily due to the belief that such faults are more realistic than automatically generated (mutation) faults. A recent empirical study, however, suggests that mutation faults can be representative of real faults. We have therefore designed and performed a controlled experiment to assess the ability of prioritization techniques to improve the rate of fault detection techniques, measured relative to mutation faults. Our results show that prioritization can be effective relative to the faults considered, and they expose ways in which that effectiveness can vary with characteristics of faults and test suites. We also compare our results to those collected earlier with respect to the relationship between hand-seeded faults and mutation faults, and the implications this has for researchers performing empirical studies of prioritization.

Incorporating Varying Test Costs and Fault Severities into Test Case Prioritization

Test case prioritization techniques schedule test cases for regression testing in an order that increases their ability to meet some performance goal. One performance goal, rate offault detection, measures how quickly faults are detected within the testing process. In previous work we provided a metric, APFD, for measuring rate of fault detection, and techniques for prioritizing test cases to improve APFD, and reported the results of experiments using those techniques. This metric and these techniques, however, applied only in cases in which test costs and fault severity are uniform. In this paper, we present a new metric for assessing the rate of fault detection of prioritized test cases, that incorporates varying test case and fault costs. We present the results of a case study illustrating the application of the metric. This study raises several practical questions that might arise in applying test case prioritization; we discuss how practitioners could go about answering these questions.

Medical Students' Attitudes Toward The Medical College Admission Test

The following study analyzed the attitudes held by pre-clinical medical students about the Medical College Admission Test or MCAT. One hundred and eighty first-year and second-year medical students at a public Midwestern medical university participated in this study. Participants completed the “Medical Students Attitudes toward the Medical College Admission Test” survey during their morning lectures near the end of their spring semester. A composite scale score of the Likert items of the survey was computed and the proportion of students with attitudes ranging from strongly agree to strongly disagree was calculated. For six of the twelve Likert items the largest proportion of participants disagreed with the statements about the MCAT and its use in the admission process and its applicability to their current medical education. Other questions included how participants prepared for the MCAT and if they completed each of the subsections were addressed as well. Future research could determine if attitudes between students accepted into medical school and those not accepted are drastically different. Advisor: Kurt F. Geisinger