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Tool support for automated fault localization in program debugging is limited because state-of-the-art algorithms often fail to provide efficient help to the user. They usually offer a ranked list of suspicious code elements, but the fault is not guaranteed to be found among the highest ranks. In Spectrum-Based Fault Localization (SBFL) – which uses code coverage information of test cases and their execution outcomes to calculate the ranks –, the developer has to investigate several locations before finding the faulty code element. Yet, all the knowledge she a priori has or acquires during this process is not reused by the SBFL tool. There are existing approaches in which the developer interacts with the SBFL algorithm by giving feedback on the elements of the prioritized list. We propose a new approach called iFL which extends interactive approaches by exploiting contextual knowledge of the user about the next item in the ranked list (e. g., a statement), with which larger code entities (e. g., a whole function) can be repositioned in their suspiciousness. We implemented a closely related algorithm proposed by Gong et al., called Talk. First, we evaluated iFL using simulated users, and compared the results to SBFL and Talk. Next, we introduced two types of imperfections in the simulation: user’s knowledge and confidence levels. On SIR and Defects4J, results showed notable improvements in fault localization efficiency, even with strong user imperfections. We then empirically evaluated the effectiveness of the approach with real users in two sets of experiments: a quantitative evaluation of the successfulness of using iFL, and a qualitative evaluation of practical uses of the approach with experienced developers in think-aloud sessions.

Traceability information can be crucial for software maintenance, testing, automatic program repair, and various other software engineering tasks. Customarily, a vast amount of test code is created for systems to maintain and improve software quality. Today’s test systems may contain tens of thousands of tests. Finding the parts of code tested by each test case is usually a difficult and time-consuming task without the help of the authors of the tests or at least clear naming conventions. Recent test-to-code traceability research has employed various approaches but textual methods as standalone techniques were investigated only marginally. The naming convention approach is a well-regarded method among developers. Besides their often only voluntary use, however, one of its main weaknesses is that it can only identify one-to-one links. With the use of more versatile text-based methods, candidates could be ranked by similarity, thus producing a number of possible connections. Textual methods also have their disadvantages, even machine learning techniques can only provide semantically connected links from the text itself, these can be refined with the incorporation of structural information. In this paper, we investigate the applicability of three text-based methods both as a standalone traceability link recovery technique and regarding their combination possibilities with each other and with naming conventions. The paper presents an extensive evaluation of these techniques using several source code representations and meta-parameter settings on eight real, medium-sized software systems with a combined size of over 1.25 million lines of code. Our results suggest that with suitable settings, text-based approaches can be used for test-to-code traceability purposes, even where naming conventions were not followed.