# AI unit test generator

> Paste source code, get unit tests.

The AI unit test generator turns a pasted function into a runnable unit test suite in the framework you choose, covering the normal path and the edge cases the code implies.

Also: unit test generator, generate unit tests, ai test generator, jest test generator, pytest generator, write tests from code, ai unit tests, generate tests from function, vitest generator, go test generator.

## What it does

Most functions are easy to test and still go untested, because writing the first test file is the slow part: the imports, the fixtures, the mock setup. This writes that file. Paste a function, pick a language, a framework and a mocking style, and get a suite back — the happy path plus the boundaries the code itself suggests, like empty inputs, missing fields and the error branches. The output goes into an editor so you can read it, copy it, or download it as a test file.

## When to use it

- You want tests for a function you have already written and do not want to start from an empty file.
- You are adding tests to a codebase that has none and need a first example to follow.
- You want to see which edge cases a function implies before deciding what to test.
- You are switching test frameworks and want to see the same suite in the new one.

## What you give it

| Input | Meaning |
| --- | --- |
| Source code | A function or module, pasted in. JavaScript, TypeScript, Python and others. |
| Framework and mocking style | Which test framework to target, and whether to use built-in mocks, hand-written stubs, or none at all. |

## What you get back

| Output | Meaning |
| --- | --- |
| Unit test suite | A test file for the chosen framework, covering the main path and the edge cases the code implies. Copyable or downloadable with the right extension. |

## Key terms

- **Unit test** — a test that exercises one function in isolation, without a database, network or filesystem. Isolation is what makes it fast enough to run on every save.
- **Mocking** — replacing a real dependency with a stand-in so the test controls what it returns. Over-mocking produces tests that pass while the code is broken, which is why the mocking style is a choice here rather than a default.
- **Edge case** — an input at a boundary — empty, zero, negative, missing, or far larger than expected. Most production bugs live at boundaries rather than in the path the author had in mind.

## Questions

### Which languages and frameworks are supported?

JavaScript, TypeScript, Python and others, with framework choices including Jest, Vitest, Mocha and pytest.

### Will the tests run as-is?

They are written to run against the code you pasted, but import paths depend on your project layout — expect to adjust those. Read generated tests before trusting them, as you would any generated code.

### Can I control how dependencies are mocked?

Yes — choose no mocking, the framework's own mocks, or hand-written stubs.


## Privacy

Unlike the browser-only tools here, this one sends the code you paste to an AI model to write the tests. Nothing is stored: the page clears when you refresh, and no account is needed.

## Links

- [Use the tool](https://www.postman.com/tools/unit-test-generator) — the interactive version of this page.
- [Postman Tools](https://www.postman.com/tools) — every free tool in this set.
- [Testing docs](https://learning.postman.com/docs/tests-and-scripts/write-scripts/test-scripts/) — Postman documentation.