Environment: - node v9.5.0 - npm 5.6.0 - yarn 1.3.2 - create-react-app 1.5.2 Steps to replicate: Just one single command. ```sh node -v && npm -v && yarn -v && create-react-app -V && cd /tmp/ && create-react-app test && cd test && yarn add -D firebase-tools && yarn test ``` Screencast: 