Stub

General

// Definition

A test double that returns canned responses to method calls, replacing real behaviour without recording or asserting on calls.

// Code Example

SinonStub a dependency for predictable returns

TypeScript

import sinon from 'sinon';
import * as api from './api';

const stub = sinon.stub(api, 'fetchUser').resolves({
  id: 1,
  name: 'Ada',
});

const user = await api.fetchUser(1);
expect(user.name).toBe('Ada');
stub.restore();

// Related terms

Mock
A test double that records how it was called and lets the test assert on those interactions. Pre-programmed with expectations about which methods will be called and how.
Spy
A test double that wraps real behaviour and records calls, so the test can both let the real code run and inspect how it was used.
Test Doubles
Umbrella term for any object that stands in for a real dependency in a test. Includes dummies, fakes, stubs, spies, and mocks — each with distinct semantics.

Learn more · Cypress with TypeScript

Chapter 4 · Lesson 2: Stubbing API Responses