Unit Test Generator - Cover Every Edge Case
Paste a function or class and get a comprehensive suite of unit tests covering happy paths, edge cases, and error conditions. Works with pytest, Jest, JUnit, and more. Free, no account required.
Testing Entire Modules?
Pro plan gives you longer context to generate tests for full classes and modules in one pass.
AI Unit Test Generator for pytest, Jest, JUnit, and More
Writing unit tests is valuable but tedious. Identifying every edge case, writing the setup and teardown, mocking dependencies, handling parameterisation - it's time-consuming work that developers defer because of deadline pressure. The AI does the analysis automatically: it reads your function, identifies the input space, and generates tests that cover cases you might miss.
Tests are written in the correct format for your framework with the right imports, correct assertion syntax, and descriptive test names. To understand code before generating tests for it, use our Code Explainer. For debugging errors the tests surface, our Error Explainer helps diagnose what went wrong. Once tests pass, our Git Commit Generator writes the correct commit message for adding them.
Frameworks Supported
What the Generated Tests Cover
Good unit tests cover more than just the happy path. The generator systematically covers the full input space.
Tests that verify the function returns the correct result for normal, expected inputs.
Empty strings, null inputs, zero values, and empty collections - the inputs that most commonly cause bugs.
Tests that verify the function raises the correct exception for invalid inputs or unexpected states.
Values at the exact boundaries of allowed ranges - the most common source of off-by-one errors.
External dependencies (APIs, databases, file I/O) are replaced with mocks so tests run fast and in isolation.
Test names describe the scenario and expected outcome - so failures tell you exactly what broke without reading the assertion.
Frequently Asked Questions
@pytest.mark.parametrize, test.each in Jest, or the equivalent for your framework.