Build test with Jest fails with `Could not locate module @/something`

I’m building an app with vuejs and testing with jest and running the tests locally works, but on circleci fails with the error

FAIL  test/unit/specs/components/ui/MessageUI.spec.js
   Test suite failed to run
    Configuration error:
    Could not locate module @/components/ui/MessageUi (mapped as /home/circleci/repo/src/components/ui/MessageUi)
    Please check:
    "moduleNameMapper": {
      "/^@\/(.*)$/": "/home/circleci/repo/src/$1"
    },
    "resolver": undefined

is not finding the component with the alias @. 😠

the failing component require:

import Component from '@/components/ui/MessageUi'

in the same folder I have another test, working, with:

import Component from '@/components/ui/TabsUi'

build: #39 repo: poc-cms test: MessageUI.spec.js#L3 component MessageUI.vue jest config for the @ alias : jest.conf.js#L11

the closest issue related, on jest: https://github.com/facebook/jest/issues/1290

[sinaa]

We faced the same issue which surprisingly passed on Windows and not on Linux (or circleci).

It turned out to be a simple file-name case sensitivity. The component’s filename was by mistake componentName rather than ComponentName.

[letanure]

changing the moduleNameMapper on jest.conf.js to remove the src breaks all tests

from

moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/src/$1'
  },

to

moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/$1'
  },