reduxjs#1944 converting test suite from Mocha to Jest (reduxjs#1951)

* Fix Jest spy code in documentation

While looking into reduxjs#1944 I noticed that the examples in the documentation
still uses expect's createSpy() instead of Jest's fn() approach

* reduxjs#1944 Converting tests from Mocha to Jest

Added Jest dependencies
Removed expect from files
Updated mocks to use `jest.fn()`
Current `expect.spyOn` replacement can be improved on
TODO: Fix linter not to complain about using `console`

* Disable eslint no-console for console related tests

* Made changes suggested by @Florian-R that enable no-args jest.fn() calls

https://github.com/reactjs/redux/pull/1951/files/927bf45f1c7666e42ae8c4c390cc726a75cab903#r78733124

* Removed moch, expect and isparta

Updated test:cov command to use jest's --coverage option

* Update typescript.spec.js

docs/recipes/WritingTests.md

@@ -304,7 +304,7 @@ import Header from '../../components/Header'
 
 function setup() {
   const props = {
-    addTodo: expect.createSpy()
+    addTodo: jest.fn()
   }
 
   const enzymeWrapper = shallow(<Header {...props} />)
@@ -333,9 +333,9 @@ describe('components', () => {
       const { enzymeWrapper, props } = setup()
       const input = enzymeWrapper.find('TodoTextInput')
       input.props().onSave('')
-      expect(props.addTodo.calls.length).toBe(0)
+      expect(props.addTodo.mock.calls.length).toBe(0)
       input.props().onSave('Use Redux')
-      expect(props.addTodo.calls.length).toBe(1)
+      expect(props.addTodo.mock.calls.length).toBe(1)
     })
   })
 })

package.json

@@ -18,9 +18,9 @@
     "lint": "npm run lint:src && npm run lint:examples",
     "lint:src": "eslint src test build",
     "lint:examples": "eslint examples",
-    "test": "cross-env BABEL_ENV=commonjs mocha --compilers js:babel-register --recursive",
+    "test": "cross-env BABEL_ENV=commonjs jest",
     "test:watch": "npm test -- --watch",
-    "test:cov": "cross-env BABEL_ENV=commonjs babel-node $(npm bin)/isparta cover $(npm bin)/_mocha -- --recursive",
+    "test:cov": "npm test -- --coverage",
     "test:examples": "cross-env BABEL_ENV=commonjs babel-node examples/testAll.js",
     "check:src": "npm run lint:src && npm run test",
     "check:examples": "npm run build:examples && npm run lint:examples && npm run test:examples",
@@ -73,6 +73,7 @@
     "babel-cli": "^6.3.15",
     "babel-core": "^6.3.15",
     "babel-eslint": "^4.1.6",
+    "babel-jest": "^15.0.0",
     "babel-loader": "^6.2.0",
     "babel-plugin-check-es2015-constants": "^6.3.13",
     "babel-plugin-transform-es2015-arrow-functions": "^6.3.13",
@@ -101,11 +102,9 @@
     "eslint": "^1.10.3",
     "eslint-config-rackt": "^1.1.1",
     "eslint-plugin-react": "^3.16.1",
-    "expect": "^1.8.0",
     "gitbook-cli": "^2.3.0",
     "glob": "^6.0.4",
-    "isparta": "^4.0.0",
-    "mocha": "^2.2.5",
+    "jest": "^15.1.1",
     "rimraf": "^2.3.4",
     "rxjs": "^5.0.0-beta.6",
     "typescript": "^1.8.0",
@@ -125,5 +124,8 @@
     "transform": [
       "loose-envify"
     ]
+  },
+  "jest": {
+    "testRegex": "(/test/.*\\.spec.js)$"
   }
 }

test/.eslintrc

@@ -1,5 +1,5 @@
 {
   "env": {
-    "mocha": true
+    "jest": true
   }
 }

test/applyMiddleware.spec.js

@@ -1,4 +1,3 @@
-import expect from 'expect'
 import { createStore, applyMiddleware } from '../src/index'
 import * as reducers from './helpers/reducers'
 import { addTodo, addTodoAsync, addTodoIfEmpty } from './helpers/actionCreators'
@@ -13,15 +12,15 @@ describe('applyMiddleware', () => {
       }
     }
 
-    const spy = expect.createSpy(() => {})
+    const spy = jest.fn()
     const store = applyMiddleware(test(spy), thunk)(createStore)(reducers.todos)
 
     store.dispatch(addTodo('Use Redux'))
     store.dispatch(addTodo('Flux FTW!'))
 
-    expect(spy.calls.length).toEqual(1)
+    expect(spy.mock.calls.length).toEqual(1)
 
-    expect(Object.keys(spy.calls[0].arguments[0])).toEqual([
+    expect(Object.keys(spy.mock.calls[0][0])).toEqual([
       'getState',
       'dispatch'
     ])
@@ -37,11 +36,11 @@ describe('applyMiddleware', () => {
       }
     }
 
-    const spy = expect.createSpy(() => {})
+    const spy = jest.fn()
     const store = applyMiddleware(test(spy), thunk)(createStore)(reducers.todos)
 
     return store.dispatch(addTodoAsync('Use Redux')).then(() => {
-      expect(spy.calls.length).toEqual(2)
+      expect(spy.mock.calls.length).toEqual(2)
     })
   })
 

test/bindActionCreators.spec.js

@@ -1,4 +1,3 @@
-import expect from 'expect'
 import { bindActionCreators, createStore } from '../src'
 import { todos } from './helpers/reducers'
 import * as actionCreators from './helpers/actionCreators'

test/combineReducers.spec.js

@@ -1,4 +1,4 @@
-import expect from 'expect'
+/* eslint-disable no-console */
 import { combineReducers } from '../src'
 import createStore, { ActionTypes } from '../src/createStore'
 
@@ -32,21 +32,24 @@ describe('Utils', () => {
     })
 
     it('warns if a reducer prop is undefined', () => {
-      const spy = expect.spyOn(console, 'error')
+      const preSpy = console.error
+      const spy = jest.fn()
+      console.error = spy
 
       let isNotDefined
       combineReducers({ isNotDefined })
-      expect(spy.calls[0].arguments[0]).toMatch(
+      expect(spy.mock.calls[0][0]).toMatch(
         /No reducer provided for key "isNotDefined"/
       )
 
-      spy.reset()
+      spy.mockClear()
       combineReducers({ thing: undefined })
-      expect(spy.calls[0].arguments[0]).toMatch(
+      expect(spy.mock.calls[0][0]).toMatch(
         /No reducer provided for key "thing"/
       )
 
-      spy.restore()
+      spy.mockClear()
+      console.error = preSpy
     })
 
     it('throws an error if a reducer returns undefined handling an action', () => {
@@ -166,7 +169,7 @@ describe('Utils', () => {
       })
 
       const initialState = reducer(undefined, '@@INIT')
-      expect(reducer(initialState, { type: 'increment' })).toNotBe(initialState)
+      expect(reducer(initialState, { type: 'increment' })).not.toBe(initialState)
     })
 
     it('throws an error on first call if a reducer attempts to handle a private action', () => {
@@ -191,17 +194,24 @@ describe('Utils', () => {
     })
 
     it('warns if no reducers are passed to combineReducers', () => {
-      const spy = expect.spyOn(console, 'error')
+      const preSpy = console.error
+      const spy = jest.fn()
+      console.error = spy
+
       const reducer = combineReducers({ })
       reducer({ })
-      expect(spy.calls[0].arguments[0]).toMatch(
+      expect(spy.mock.calls[0][0]).toMatch(
         /Store does not have a valid reducer/
       )
-      spy.restore()
+      spy.mockClear()
+      console.error = preSpy
     })
 
     it('warns if input state does not match reducer shape', () => {
-      const spy = expect.spyOn(console, 'error')
+      const preSpy = console.error
+      const spy = jest.fn()
+      console.error = spy
+
       const reducer = combineReducers({
         foo(state = { bar: 1 }) {
           return state
@@ -212,69 +222,75 @@ describe('Utils', () => {
       })
 
       reducer()
-      expect(spy.calls.length).toBe(0)
+      expect(spy.mock.calls.length).toBe(0)
 
       reducer({ foo: { bar: 2 } })
-      expect(spy.calls.length).toBe(0)
+      expect(spy.mock.calls.length).toBe(0)
 
       reducer({
         foo: { bar: 2 },
         baz: { qux: 4 }
       })
-      expect(spy.calls.length).toBe(0)
+      expect(spy.mock.calls.length).toBe(0)
 
       createStore(reducer, { bar: 2 })
-      expect(spy.calls[0].arguments[0]).toMatch(
+      expect(spy.mock.calls[0][0]).toMatch(
         /Unexpected key "bar".*createStore.*instead: "foo", "baz"/
       )
 
       createStore(reducer, { bar: 2, qux: 4, thud: 5 })
-      expect(spy.calls[1].arguments[0]).toMatch(
+      expect(spy.mock.calls[1][0]).toMatch(
         /Unexpected keys "qux", "thud".*createStore.*instead: "foo", "baz"/
       )
 
       createStore(reducer, 1)
-      expect(spy.calls[2].arguments[0]).toMatch(
+      expect(spy.mock.calls[2][0]).toMatch(
         /createStore has unexpected type of "Number".*keys: "foo", "baz"/
       )
 
       reducer({ corge: 2 })
-      expect(spy.calls[3].arguments[0]).toMatch(
+      expect(spy.mock.calls[3][0]).toMatch(
         /Unexpected key "corge".*reducer.*instead: "foo", "baz"/
       )
 
       reducer({ fred: 2, grault: 4 })
-      expect(spy.calls[4].arguments[0]).toMatch(
+      expect(spy.mock.calls[4][0]).toMatch(
         /Unexpected keys "fred", "grault".*reducer.*instead: "foo", "baz"/
       )
 
       reducer(1)
-      expect(spy.calls[5].arguments[0]).toMatch(
+      expect(spy.mock.calls[5][0]).toMatch(
         /reducer has unexpected type of "Number".*keys: "foo", "baz"/
       )
 
-      spy.restore()
+      spy.mockClear()
+      console.error = preSpy
     })
 
     it('only warns for unexpected keys once', () => {
-      const spy = expect.spyOn(console, 'error')
+      const preSpy = console.error
+      const spy = jest.fn()
+      console.error = spy
+
       const foo = (state = { foo: 1 }) => state
       const bar = (state = { bar: 2 }) => state
 
-      expect(spy.calls.length).toBe(0)
+      expect(spy.mock.calls.length).toBe(0)
       const reducer = combineReducers({ foo, bar })
       const state = { foo: 1, bar: 2, qux: 3 }
       reducer(state, {})
       reducer(state, {})
       reducer(state, {})
       reducer(state, {})
-      expect(spy.calls.length).toBe(1)
+      expect(spy.mock.calls.length).toBe(1)
       reducer({ ...state, baz: 5 }, {})
       reducer({ ...state, baz: 5 }, {})
       reducer({ ...state, baz: 5 }, {})
       reducer({ ...state, baz: 5 }, {})
-      expect(spy.calls.length).toBe(2)
-      spy.restore()
+      expect(spy.mock.calls.length).toBe(2)
+
+      spy.mockClear()
+      console.error = preSpy
     })
   })
 })

test/compose.spec.js

@@ -1,4 +1,3 @@
-import expect from 'expect'
 import { compose } from '../src'
 
 describe('Utils', () => {