reduce-redux/test.js

A helper library to reduce redux boilerplate and make developers life easier.

const assert = require('assert')
const sinon = require('sinon')
const createReducer = require('./').createReducer

describe('createReducer', () => {

  describe('default behaviour and primitive data type state', () => {

    const spyAction = () => ({ type: 'SPY_ACTION' })
    const setState = state => ({ type: 'SET_STATE', state })
    const randomAction = () => ({ type: 'RANDOM_ACTION' })
  
    const spy = sinon.spy()
  
    const initialState = 'State'
  
    const actionMap = {
      SPY_ACTION: spy,
      SET_STATE: action => action.state
    }

    it('should return initial state when no previous state is provided', () => {
      const reducer = createReducer(initialState, actionMap)
      const result = reducer(undefined)
      assert.strictEqual(result, initialState)
    })
  
    it('should return previous state if no action is provided in the given action map', () => {
      const reducer = createReducer(initialState, actionMap)
      const result = reducer(initialState, randomAction())
      assert.strictEqual(result, initialState)
    })

    it('should return relevant action map function result', () => {
      const reducer = createReducer(initialState, actionMap)
      const result = reducer(initialState, setState('New name'))
      assert.strictEqual(result, 'New name')
    })

    it('should provide action and state for the given action map function', () => {
      const reducer = createReducer(initialState, actionMap)
      reducer(initialState, spyAction())
      assert.ok(spy.calledWithExactly(spyAction(), initialState))
    })
  })

  describe('object data type state', () => {

    const setPersonId = id => ({ type: 'PERSON_SET_ID', id })
    const setPersonName = name => ({ type: 'PERSON_SET_NAME', name })
    const deletePerson = () => ({ type: 'PERSON_DELETE' })

    const initialState = { name: 'Old name', id: 123 }
  
    const actionMap = {
      PERSON_SET_NAME: action => ({ name: action.name }),
      PERSON_SET_ID: action => ({ id: action.id }),
      PERSON_DELETE: () => null
    }

    it('should merge returned state and previous state if both are objects', () => {
      const reducer = createReducer(initialState, actionMap)
      const result = reducer(initialState, setPersonName('New name'))
      assert.deepEqual(result, { name: 'New name', id: 123 })
    })

    it('should set the state correctly with different actions', () => {
      const reducer = createReducer(initialState, actionMap)
      const result = reducer(initialState, setPersonName('New name'))
      const result2 = reducer(result, setPersonId(456))
      assert.deepEqual(result2, { name: 'New name', id: 456 })
    })
  
    it('should set null if it is returned by action map function', () => {
      const reducer = createReducer(initialState, actionMap)
      const result = reducer(initialState, deletePerson())
      assert.equal(result, null)
    })
  })
})