Ubuntu 18.04 / error install yarn / ERROR: There are no scenarios; must have at least one.

Pasa en varias versiones anteriores de Ubuntu, cito los comandos para solucionarlo:

sudo apt remove cmdtest
sudo apt remove yarn
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt update
sudo apt install yarn

Fuente: https://github.com/yarnpkg/yarn/issues/2821