About Unit Test Generator
Scaffolds JavaScript/TypeScript unit tests from a pasted function signature. Detects function name and parameters using regex pattern matching (supports function declarations, const arrow functions, and const function expressions), then generates test boilerplate for Jest, Mocha, Vitest, or Jasmine. Produces tests for typical input, edge cases (empty/zero/false values), and error handling (null/undefined), with heuristic sample values chosen based on parameter names.
- Parses three function patterns: function foo(), const foo = () =>, and const foo = function()
- Heuristic sample values: params containing “text”/“str” get string values, “arr”/“list” get arrays, “count”/“num” get numbers, “flag”/“is” get booleans
- Generates framework-appropriate imports (jest/globals, vitest, mocha+chai, or jasmine globals)
- Toggles for including edge cases and error handling tests
- Output downloadable as .test.ts (Vitest) or .test.js (others)
Frequently Asked Questions
- Does it actually analyze what the function does?
- No. It reads the function signature (name and parameter names) and generates skeleton tests with heuristic sample values. You need to fill in the actual expected return values and assertions. It’s a scaffolding tool, not an AI test writer.
- Which testing framework should I pick?
- Jest is the most popular for React and general JavaScript projects. Vitest is faster and native to Vite-based projects. Mocha offers more flexibility with plugin-based assertions (uses Chai here). Jasmine is common in Angular. Pick whatever your project already uses.