Mastering React Test-Driven Development

Scaffolding a reducer

Our saga file actually needs to contain two things: the saga that we've just scaffolded, and a reducer that we can use to make state changes. In this section, we'll make a start adding our first action, ADD_CUSTOMER_SUBMITTING. We'll complete it later in the chapter:

1. Stay in test/sagas/customer.test.js, and import the reducer function:

import { reducer } from '../../src/sagas/customer';

2. Add a new describe block to the bottom of the file (not nested within the first describe block). This shows that if the reducer is invoked with an unknown action, our reducer should return a default state for our object. This is a standard behavior for Redux reducers, so you should almost always start with a test like this for your ...