Towards Understanding the Effectiveness of Large Language Models on Directed Test Input Generation

Automatic testing has garnered significant attention and success over the past few decades. Techniques such as unit testing and coverage-guided fuzzing have revealed numerous critical software bugs and vulnerabilities. However, a long-standing, formidable challenge for existing techniques is how to achieve higher testing coverage. Constraint-based techniques, such as symbolic execution and concolic testing, have been well-explored and integrated into the existing approaches. With the popularity of Large Language Models (LLMs), recent research efforts to design tailored prompts to generate inputs that can reach more uncovered target branches. However, the effectiveness of using LLMs for generating such directed inputs and the comparison with the proven constraint-based solutions has not been systematically explored.