Jest React - Test suite failed to run, Cannot find module 'react-dotenv'

Question

I used Create React App to make a new project, and now i try to implement each feature i will need.

I am facing an issue i dont understand while trying to configure jest with reactjs. One my node_modules, react-dotenv break jest test.

If i try to copy/past the issue line import env from 'react-dotenv'; directly in the root tested file Login.tsx there is no error. I tried to configure moduleNameMapper and search around without success..

I dont understand the problem, what am i missing?

Answer 1

Ok, i was missing mocks and transformIgnorePatterns Didn't really make transformIgnorePatterns working using:

transformIgnorePatterns: ["node_modules/(?!react-dotenv)"],

but the mocks

moduleNameMapper: {
  '^.+\\.(css|scss)$': '<rootDir>/__mocks__/CSSStub.config.js',
  'react-dotenv': '<rootDir>/__mocks__/react-dotenv.tsx'
},

did the job.