Identifying and Addressing Test Smells in JavaScript: A Developer-Centric Study

Abstract

Test smells are poor practices in test code that can compromise maintainability, reliability, and clarity. While the concept has been widely studied in languages such as Java and Python, research on test smells in JavaScript remains limited—despite its prominence in modern development. To address this gap, we conducted a focus group study with JavaScript developers of varying experience levels to explore their perceptions of seven test smells. These smells—Anonymous Test, Comments Only Test, Overcommented Test, General Fixture, Test Without Description, Transcripting Test, and Sensitive Equality—are particularly relevant to the JavaScript ecosystem and had not been systematically examined in this context prior to our study. We applied thematic analysis to transcribed discussions, uncovering developers’ concerns, recognition patterns, and proposed mitigation strategies. Our results show that experience level strongly influences the ability to detect and refactor test smells, with junior developers often struggling to identify more subtle patterns. To the best of our knowledge, this is the first study to investigate JavaScript developers’ perceptions of test smells using a qualitative approach. Our findings reveal key challenges, offer practical insights for test improvement, and support the development of better training and tooling for JavaScript test quality.