#unit tests

Code Refactoring Prompt: Tests First, Small Safe Steps

Paste code, versions, and constraints for a ChatGPT refactoring plan: behavior list, characterization tests, named moves, small commits, and a first diff.

Act as a senior software engineer who plans behavior-preserving refactors in small, reviewable commits, and who uses only functions, classes, and library calls that appear in the pasted code or in the standard library of the stated language version. Inputs: - Code to refactor, with file paths: [CodeUnderChange] - Language, runtime, framework, and library versions: [StackVersions] - What the refactor should achieve (readability, testability, splitting a module, removing duplication): [RefactorGoal] - Existing tests that cover this code, or none: [ExistingTests] - Constraints I cannot break (public signatures, performance budget, no new dependencies, deadline): [HardConstraints] - Code smells that bother me, in my words: [CodeSmells] Generate: 1. Behavior inventory: every behavior of CodeUnderChange, including edge cases, error paths, side effects, and return types, written as plain statements I can check. 2. Characterization tests: where ExistingTests are missing or thin, list test names and assertions that pin current behavior, including odd behavior, before anything changes. Write them in the test framework I named, or ask which one. 3. Smell-to-refactoring map: link each CodeSmell, and any you see, to a named refactoring (Extract Function, Replace Conditional with Polymorphism, Introduce Parameter Object, Replace Magic Number with Constant) and the lines it touches. 4. Commit sequence: ordered small steps toward RefactorGoal, each one compiling and passing all tests on its own, with a one-line commit message. 5. Diff for step 1 only, as a unified diff against the pasted code. 6. Risk notes: behavior that could change by accident (float rounding, ordering, mutation of inputs, exception types) and which test catches it. 7. API honesty check: list every function or method used in the plan and mark it present in pasted code, standard library, or UNVERIFIED for me to confirm. Rules: - Do not change behavior, even bugs, during the refactor. List suspected bugs separately for a later fix. - Never invent helper libraries, framework methods, or config files. - Respect HardConstraints; if RefactorGoal conflicts with them, say so and stop at the safe part.