Serious games can teach essential coding and testing concepts even to younger audiences. In the Code Critters game critters execute short snippets of block-based code while traversing the game map, and players position magical portals (akin to test oracles) at locations (akin to test inputs) to distinguish between critters executing correct code from those who execute faulty code. However, this adaptation of the tower defense genre limits code under test to basic sequences and branches, and excludes the fundamental programming concept of loops. To address this limitation, in this paper we introduce an entirely new game concept integrated into the Code Critters storyline, tasking players to test the behavior of critters collecting ingredients for a healing potion using loop-based recipes at a second-stage level. In a study involving 29 secondary school students, we observed active engagement with these new loop-integrated levels. The results highlight challenges the students face, which can inform future strategies for improving coding and testing education.

The integration of Large Language Models (LLMs), such as ChatGPT and GitHub Copilot, into software engineering workflows has shown potential to enhance productivity, particularly in software testing. This paper investigates whether LLM support improves defect detection effectiveness during unit testing. Building on prior studies comparing manual and tool-supported testing, we replicated and extended an experiment where participants wrote unit tests for a Java-based system with seeded defects within a time-boxed session, supported by LLMs. Comparing LLM supported and manual testing, results show that LLM support significantly increases the number of unit tests generated, defect detection rates, and overall testing efficiency. These findings highlight the potential of LLMs to improve testing and defect detection outcomes, providing empirical insights into their practical application in software testing.

Java remains one of the most popular programming languages in education. Although Java programming education is well supported by study materials, learners also need more immediate support on the problems they face in their own code. When this support cannot be offered by educators personally, learners can resort to automated program analysis tools such as linters, which provide feedback on potential bugs or code issues. This is constructive feedback, but it may nevertheless feel like criticism. This paper introduces code perfumes for Java, a simple program analysis technique similar to linting, but commending the correct application of good programming practices. We present a catalogue of 20 Java code perfumes related to common Java language constructs for beginner to immediate learners. Our evaluation shows that these code perfumes occur frequently in learners' code, and programs with more code perfume instances tend to have better functionality and readability. Moreover, students who incorporate more code perfumes tend to achieve higher grades. Thus, code perfumes serve as a valuable tool to acknowledge learners' successes, and as a means to inform instructors about their learners' progress.

Testing is an important aspect of software development, but unfortunately, it is often neglected. While test quality analyses such as code coverage or mutation analysis inform developers about the quality of their tests, such reports are viewed only sporadically during continuous integration or code review, if they are considered at all, and their impact on the developers' testing behavior therefore tends to be negligible. To actually influence developer behavior, it may rather be necessary to motivate developers directly within their programming environment, while they are coding. We introduce IntelliGame, a gamified plugin for the popular IntelliJ Java Integrated Development Environment, which rewards developers for positive testing behavior using a multi-level achievement system: A total of 27 different achievements, each with incremental levels, provide affirming feedback when developers exhibit commendable testing behavior, and provide an incentive to further continue and improve this behavior. A controlled experiment with 49 participants given a Java programming task reveals substantial differences in the testing behavior triggered by IntelliGame: Incentivized developers write more tests, achieve higher coverage and mutation scores, run their tests more often, and achieve functionality earlier.

Software is infamous for its poor quality and frequent occurrence of bugs. While there is no doubt that thorough testing is an appropriate answer to ensure sufficient quality, the poor state of software generally suggests that developers may not always engage as thoroughly with testing as they should. This observation aligns with the prevailing belief that developers simply do not like writing tests. In order to determine the truth of this belief, we conducted a comprehensive survey with 21 questions aimed at (1) assessing developers’ current engagement with testing and (2) identifying factors influencing their inclination toward testing; that is, whether they would actually like to test more but are inhibited by their work environment, or whether they would really prefer to test even less if given the choice. Drawing on 284 responses from professional software developers, we uncover reasons that positively and negatively impact developers’ motivation to test. Notably, reasons for motivation to write more tests encompass not only a general pursuit of software quality but also personal satisfaction. However, developers nevertheless perceive testing as mundane and tend to prioritize other tasks. One approach emerging from the responses to mitigate these negative factors is by providing better recognition for developers’ testing efforts.