Test Generation
Create thorough, maintainable test suites covering happy paths, edge cases, and error handling.
Test Design
| Principle | Application |
|---|---|
| Clear names | should return X when Y |
| AAA pattern | Arrange → Act → Assert |
| One behavior | Each test verifies one thing |
| Isolation | No shared state between tests |
| Specific asserts | toEqual([1,2,3]) not toBeTruthy() |
Coverage Checklist
- •✓ Happy path: Normal operation
- •✓ Edge cases: null, empty, 0, -1, MAX_INT, special chars
- •✓ Errors: Invalid inputs, missing params, exceptions
- •✓ Integration: External deps mocked
Framework Quick Reference
| Framework | Structure | Assert | Mock |
|---|---|---|---|
| Jest | describe/it | expect().toBe/toEqual | jest.mock() |
| pytest | test_name() | assert x == y | mocker.patch() |
| JUnit | @Test | assertEquals() | @Mock + Mockito |
| Mocha | describe/it | Chai expect().to | Sinon |
| RSpec | describe/it | expect().to eq | allow().to receive |
| Go | TestName(t) | t.Error() | Manual/testify |
Mocking Strategy
Mock: API calls, DB, file system, time, external services
Don't mock: Simple data, pure functions, code under test
Example Structure
javascript
describe('UserService', () => {
describe('createUser', () => {
it('should create user with valid data', () => {
// Arrange
const data = { name: 'John', email: 'john@test.com' }
// Act
const user = createUser(data)
// Assert
expect(user.name).toBe('John')
})
it('should throw when email invalid', () => {
expect(() => createUser({ email: 'bad' })).toThrow(ValidationError)
})
})
})