package.json

...
"scripts": {
    "start": "react-app-rewired start",
    "build": "react-app-rewired build",
    "test": "react-app-rewired test",
    "eject": "react-scripts eject"
  }
...
  "jest": {
    "moduleNameMapper": {
      "^~\/(.*)$": "<rootDir>/src/$1"
    }
  }