Jest Could not locate module FileName.css (mapped as identity-obj-proxy)

Question

I've been trying to set up a testing environment for my React project and I had a problem with Unexpected token when importing the CSS file. i added the moduleNameMapper to the package.json to fix it and now i'm facing this issue. Does anyone know what can i do to fix this?

> [email protected] test C:\Users\admin\Documents\myApp
> jest

FAIL _tests_\Home.test.js
  ● Test suite failed to run

    Configuration error:

    Could not locate module react-datepicker/dist/react-datepicker-cssmodules.css (mapped as identity-obj-proxy)

    Please check:

    "moduleNameMapper": {
      "/^.+\.(css|less)$/": "identity-obj-proxy"
    },
    "resolver": undefined

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        1.894s
Ran all test suites.
npm ERR! Test failed.  See above for more details.

jest portion of package.json

  "jest": {
    "transform": {
      "^.+\\.jsx?$": "babel-jest"
    },
    "moduleNameMapper": {
      "\\.(s?css|less)$": "identity-obj-proxy"
    }
  },

Answer 1

make sure you have identity-obj-proxy in your devDependencies

"devDependencies": {
  "identity-obj-proxy": "^3.0.0",
  ...
}

if not, run

npm install --save-dev identity-obj-proxy

Answer 2

make sure that you have identity-obj-proxy npm package in your devDependencies list.

Answer 3

In my case, the complaint came because a recent version of jest decided to enforce file extensions, and my package.json config was missing "scss"

"moduleFileExtensions": [
      "js",
      "json",
      "vue",
      "scss"
    ],

Answer 4

We fixed this error by downgrading Jest back to 20.0.4, after updating to 21.0.1 and breaking our build with this error