Coverage Goal Selector for Combining Multiple Criteria in Search-Based Unit Test Generation

TL;DR

This paper introduces a novel smart selection approach for combining multiple coverage criteria in search-based unit test generation, improving coverage and bug detection efficiency by selecting optimal coverage goals.

Contribution

The paper proposes a new method called smart selection that reduces optimization objectives by selecting relevant coverage goals based on their correlations and relationships, enhancing test generation effectiveness.

Findings

Smart selection outperforms combining all goals in 65.1% of cases.

It improves coverage and bug detection over varying budgets.

Experimental results validate the assumptions about coverage criteria relationships.

Abstract

Unit testing is critical to the software development process, ensuring the correctness of basic programming units in a program (e.g., a method). Search-based software testing (SBST) is an automated approach to generating test cases. SBST generates test cases with genetic algorithms by specifying the coverage criterion (e.g., branch coverage). However, a good test suite must have different properties, which cannot be captured using an individual coverage criterion. Therefore, the state-of-the-art approach combines multiple criteria to generate test cases. Since combining multiple coverage criteria brings multiple objectives for optimization, it hurts the test suites' coverage for certain criteria compared with using the single criterion. To cope with this problem, we propose a novel approach named \textbf{smart selection}. Based on the coverage correlations among criteria and the subsumption relationships among coverage goals, smart selection selects a subset of coverage goals to reduce the number of optimization objectives and avoid missing any properties of all criteria. We conduct experiments to evaluate smart selection on $400$ Java classes with three state-of-the-art genetic algorithms under the $2$-minute budget. On average, smart selection outperforms combining all goals on $65.1\%$ of the classes having significant differences between the two approaches. Secondly, we conduct experiments to verify our assumptions about coverage criteria relationships. Furthermore, we assess the coverage performance of smart selection under varying budgets of $5$, $8$, and $10$ minutes and explore its effect on bug detection, confirming the advantage of smart selection over combining all goals.