Test

Unit Test Generator

Generate comprehensive unit tests for code.

Workflow

1. Detect the testing ecosystem:

   • Check for existing test config: jest.config.*, vitest.config.*, pytest.ini, pyproject.toml [tool.pytest], Cargo.toml, .rspec, go test.
   • Check for existing test files to match patterns and conventions.
   • Identify the test runner, assertion library, and mocking framework in use.

2. Analyze the target code:

   • Read the function/class/module to test.
   • Identify: inputs, outputs, side effects, dependencies, edge cases, error paths.
   • Map out the code paths (happy path, error paths, boundary conditions).

3. Generate tests following the project's patterns:

   • Match existing file naming: *.test.ts, *_test.go, test_*.py, *_spec.rb, etc.
   • Match existing directory structure (__tests__/, tests/, co-located, etc.).
   • Use the same assertion style and patterns as existing tests.

4. Write tests covering:

Test Categories

5. Structure each test with AAA pattern:

   • Arrange — set up preconditions and inputs.
   • Act — execute the code under test.
   • Assert — verify the expected outcome.

6. Run the tests to ensure they pass.

Guidelines

• Tests should be independent — no shared mutable state between tests.
• Use descriptive test names that explain the scenario: "returns empty array when input is empty".
• Mock external dependencies (APIs, databases, file system) but not the code under test.
• Prefer toEqual deep comparison over toBe reference comparison for objects.
• If the code is untestable, suggest refactoring to improve testability.
• Don't test implementation details — test behavior and public interfaces.
• Include at least one negative test (what should NOT happen).