Cursor Test Writer
Added Apr 2, 2026
About This Prompt
This prompt generates comprehensive test suites that go far beyond basic happy-path testing. It produces tests organized into logical categories covering edge cases, error handling, integration points, and regression scenarios that developers often miss. Each test follows the arrange-act-assert pattern with descriptive naming conventions that serve as living documentation. The prompt handles mock setup, fixture creation, and test organization so you get a production-ready test file. This is invaluable for developers who know they should write more tests but struggle with identifying what to test, and for teams looking to increase their code coverage systematically.
Variables to Customize
[LANGUAGE]
Programming language of the code to test
Example: TypeScript
[TEST_FRAMEWORK]
Testing framework to use
Example: Jest with React Testing Library
[FUNCTIONALITY]
What the code does
Example: a shopping cart service with add, remove, and calculate total operations
[PROJECT_TYPE]
Type of application
Example: e-commerce React application
[CODE_BLOCK]
The code to write tests for
Example: // paste your code here
[COVERAGE_TARGET]
Target code coverage percentage
Example: 90%
Tips for Best Results
- Include your actual code for the most accurate and relevant test generation
- Focus on testing behavior rather than implementation details for more resilient tests
- Use the generated tests as a starting point and add domain-specific edge cases you know about
Example Output
describe('ShoppingCartService', () => {
let cart: ShoppingCartService;
let mockProductRepo: jest.Mocked<ProductRepository>;
beforeEach(() => {
mockProductRepo = createMockProductRepo();
cart = new ShoppingCartService(mockProductRepo);
});
describe('addItem', () => {
it('should add a new item with quantity 1 when item is not in cart', async () => {
// Arrange
const product = createTestProduct({ id: '1', price: 29.99 });
mockProductRepo.findById.mockResolvedValue(product);
// Act
await cart.addItem('1');
// Assert
expect(cart.getItems()).toHaveLength(1);
expect(cart.getItems()[0].quantity).toBe(1);
});
it('should increment quantity when adding an existing item', ...
it('should throw InvalidProductError when product ID does not exist', ...