vamseeachanta Mock Management (+2)
Mock Management
- Keep mocks simple and focused on single behavior
- Verify interactions, not implementation details
- Use
jest.fn()for behavior verification - Avoid over-mocking internal details
- Reset mocks between tests
Contract Design
- Define clear interfaces through mock expectations
- Focus on object responsibilities and collaborations
- Use mocks to DRIVE design decisions
- Keep contracts minimal and cohesive
Common Pitfalls
// BAD: Over-mocking internal details
const mock = {
_internalState: {},
_privateMethod: jest.fn() // Don't mock private methods
};
// GOOD: Mock only public interface
const mock = {
publicMethod: jest.fn().mockReturnValue(expectedResult)
};
// BAD: Verifying too many implementation details
expect(mock.method).toHaveBeenCalledTimes(3); // Fragile
// GOOD: Verify essential behavior
expect(mock.method).toHaveBeenCalledWith(expectedArgs);