Stuff I've put together,

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KAIST Automated Software Testing · Semester-long team project

ASTraMut

Java mutation-operator learner: mines AST-level edit patterns from real bug-fix commits (ManySStuBs4J + Bugs2Fix), generalizes them via anti-unification, and reverses the learned fixes into mutants. Scores 1.94% lower than PIT's default mutation score on Defects4J while reaching bug shapes — API renames, predicate rewrites, block restructuring — PIT's fixed operator set can't express.
Venn diagram of the overlap between ManySStuBs4J, Bugs2Fix, and PIT default mutation operators