jest: add 'src' path to jest default config

[jangxyz]

Importing from absolute paths in test files throws "Cannot find module" error.

Currently this test code:

import { render } from '@redwoodjs/testing'

import HomePage from './HomePage'
import data from 'src/model/data' // <-- here

describe('HomePage', () => {
  it('renders successfully', () => {
    expect(() => {
      render(<HomePage />)
    }).not.toThrow()
  })

  it('reads data', () => {
    expect(data).toBe(3)
  })
})

throws error:

Changing it to relative path (import data from '../../model/data') works fine.

As redwood supports src path alias out of the box, it seems natural to expect the same for test codes as well.

I got it working by adding moduleNameMapper configuration to web/config/jest.config.js:
(from jest configuration#moduleNameMapper)

config.moduleNameMapper = config.moduleNameMapper || {}
config.moduleNameMapper['src/(.*)'] = '<rootDir>/src/$1'

Since like jest.createConfig.ts is already using moduleNameMapper heavily,

redwood/packages/core/src/configs/browser/jest.createConfig.ts

Lines 20 to 47 in f0b2ac5

	moduleNameMapper: {
	/**
	* Make sure modules that require different versions of these
	* dependencies end up using the same one.
	*/
	'^react$': path.join(NODE_MODULES_PATH, 'react'),
	'^react-dom$': path.join(NODE_MODULES_PATH, 'react-dom'),
	'^@apollo/client/react$': path.join(
	NODE_MODULES_PATH,
	'@apollo/client/react'
	),
	// We replace imports to "@redwoodjs/router" with our own implementation.
	'^@redwoodjs/router$': path.join(
	NODE_MODULES_PATH,
	'@redwoodjs/testing/dist/MockRouter.js'
	),
	'^@redwoodjs/web$': path.join(NODE_MODULES_PATH, '@redwoodjs/web'),
	'^@redwoodjs/testing$': path.join(
	NODE_MODULES_PATH,
	'@redwoodjs/testing'
	),
	'~__REDWOOD__USER_ROUTES_FOR_MOCK': getPaths().web.routes,
	/**
	* Mock out files that aren't particularly useful in tests. See fileMock.js for more info.
	*/
	'\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga|css)$':
	'@redwoodjs/testing/dist/fileMock.js',
	},

I think it would be plausible to add src alias too.

[peterp]

Weird, this should be handled by babel - which jest should be using

[jtoar]

@dac09 fixed this in a recent release (perhaps the last one even):