Add Tests

Workflow

1. •Identify the package under packages/ that contains the target function.
2. •Find or create a test file in packages/<pkg>/__tests__/.
3. •Follow the naming pattern:
   • •describe('functionName', () => { it('should ...') })
4. •Cover at least:
   • •Common expected behavior
   • •Edge cases
5. •Use deterministic inputs and avoid external I/O unless required.
6. •Suggest running focused tests:
   • •TEST_API=<package> npm run test