how to unmock a single instance method with jest

Question

coming from rspec, i am having trouble understanding mocking with jest. the approach i am trying for, is to automock a class's constructor and all of it's functions, and then unmock them one by one to test only that one function. the only documentation i can find on it, is with using 2 classes, mocking 1 class, and then testing that those functions are called from the other unmocked class.

below is a basic, contrived idea of what i am trying to do. can someone direct me to the jest-way of doing this?

foo.js

class Foo
  constructor: ->
    this.bar()
    this.baz()
  bar: ->
    return 'bar'
  baz: ->
    return 'baz'

foo_test.js

// require the class
Foo = require('foo')

// mock entire Foo class methods
jest.mock('foo')

// unmock just the bar method
jest.unmock(Foo::bar)

// or by
Foo::bar.mockRestore()

// and should now be able to call
foo = new Foo
foo.bar() // 'bar'
foo.baz() // undefined (still mocked)

// i even tried unmocking the instance
foo = new Foo
jest.unmock(foo.bar)
foo.bar.mockRestore()

Answer 1

mockFn.mockRestore() worked for me with [email protected]:

// Create a spy with a mock
const consoleInfoSpy = jest.spyOn(console, 'info').mockImplementation(() => {})

// Run test or whatever code which uses console.info
console.info('This bypasses the real console.info')

// Restore original console.info
consoleInfoSpy.mockRestore()

Answer 2

This does not strictly apply to the OP, but answer-seekers may end up here. You can mock a module except certain parts for all tests like so.

mocks/saladMaker.js

// Let Jest create the mock.
const saladMaker = jest.genMockFromModule('../saladMaker');

// Get the unmocked chop method.
const {chop} = require.requireActual('../saladMaker');

// Patch it in.
saladMaker.chop = chop;

module.exports = saladMaker;

The key part is to use requireActual to get at the unmocked module.

bypassing module mocks

Update

require.requireActual has been replaced with jest.requireActual.