hoist-jest.spec.ts

import { testing } from 'bs-logger'
import * as tsc from 'typescript'

import * as hoist from './hoist-jest'

const CODE_WITH_HOISTING_NO_JEST_GLOBALS = `
import React from 'react'
import Unmocked from '../__test_modules__/Unmocked'
import Mocked from '../__test_modules__/Mocked'
import a from '../__test_modules__/a'
import b from '../__test_modules__/b'
import c from '../__test_modules__/c'
import d from '../__test_modules__/d'
import f from '../__test_modules__/f'
import jestBackticks from '../__test_modules__/jestBackticks'

// The virtual mock call below will be hoisted above this \`require\` call.
const virtualModule = require('virtual-module')

// These will all be hoisted above imports
jest.unmock('react')
jest.deepUnmock('../__test_modules__/Unmocked')
jest.unmock('../__test_modules__/c').unmock('../__test_modules__/d')

let e;
(function () {
  const _getJestObj = 42;
  e = require('../__test_modules__/e').default
  // hoisted to the top of the function scope
  jest.unmock('../__test_modules__/e')
})()

jest.mock('../__test_modules__/f', () => {
  if (!global.CALLS) {
    global.CALLS = 0
  }
  global.CALLS++

  return {
    _isMock: true,
    fn: () => {
      // The \`jest.mock\` transform will allow require, built-ins and globals.
      const path = require('path')
      const array = new Array(3)
      array[0] = path.sep
      return jest.fn(() => array)
    },
  };
})
jest.mock(\`../__test_modules__/jestBackticks\`)
jest.mock('virtual-module', () => 'kiwi', {virtual: true})
// This has types that should be ignored by the out-of-scope variables check.
jest.mock('has-flow-types', () => (props: {children: mixed}) => 3, {
  virtual: true,
})

// These will not be hoisted
jest.unmock('../__test_modules__/a').dontMock('../__test_modules__/b')
jest.unmock('../__test_modules__/' + 'a')
jest.dontMock('../__test_modules__/Mocked')
{
  const jest = {unmock: () => {}};
  // Would error (used before initialization) if hoisted to the top of the scope
  jest.unmock('../__test_modules__/a')
}

// This must not throw an error
const myObject = {mock: () => {}}
myObject.mock('apple', 27)

// Variable names prefixed with \`mock\` (ignore case) should not throw as out-of-scope
const MockMethods = () => {}
jest.mock('../__test_modules__/f', () => MockMethods)

console.log(Unmocked)
console.log(Mocked)
console.log(a)
console.log(b)
console.log(c)
console.log(d)
console.log(e)
console.log(virtualModule)
console.log(jestBackticks)
`
const CODE_WITH_HOISTING_HAS_JEST_GLOBALS = `
  import a from '../__test_modules__/a'
  import b from '../__test_modules__/b'

  import {jest} from '@jest/globals'
  import {jest as aliasedJest} from '@jest/globals'
  import * as JestGlobals from '@jest/globals'

  import c from '../__test_modules__/c'
  import d from '../__test_modules__/d'

  // These will be hoisted above imports

  jest.unmock('../__test_modules__/a')
  aliasedJest.unmock('../__test_modules__/b')
  JestGlobals.jest.unmock('../__test_modules__/c')

  // These will not be hoisted above imports

  {
    const jest = {unmock: () => {}};
    jest.unmock('../__test_modules__/d');
  }

  console.log(a)
  console.log(b)
  console.log(c)
  console.log(d)
`

const logger = testing.createLoggerMock()
const createFactory = () => hoist.factory({ logger, compilerModule: tsc } as any)
const transpile = (source: string) => tsc.transpileModule(source, { transformers: { before: [createFactory()] } })

describe('hoisting', () => {
  it('should have correct signature', () => {
    expect(hoist.name).toBe('hoisting-jest-mock')
    expect(typeof hoist.version).toBe('number')
    expect(hoist.version).toBeGreaterThan(0)
    expect(typeof hoist.factory).toBe('function')
  })

  it.each([CODE_WITH_HOISTING_NO_JEST_GLOBALS, CODE_WITH_HOISTING_HAS_JEST_GLOBALS])(
    'should hoist correctly jest methods',
    (data) => {
      const out = transpile(data)

      expect(out.outputText).toMatchSnapshot()
    },
  )
})