Writing Unit Tests with Jest

test('validates user input', () => {
  expect(() => {
    validateUser({ name: '' });
  }).toThrow('Name is required');
});

Testing async errors
Testing error messages
This demonstrates proper error message testing: 1) Verifies specific error messages, 2) Uses function wrapper to catch thrown errors, 3) Ensures precise error handling, 4) Validates error messages match expectations, 5) Important for user feedback accuracy, 6) Helps maintain consistent error messaging, 7) Essential for API contract testing, 8) Improves debugging and maintenance.
Testing error types
Testing error conditions