Ember test generators do not generate files

The following command from the Ember tutorial doesn't create any files:

ember g acceptance-test list-rentals

It outputs only this single line:

super-rentals % ember g acceptance-test list-rentals
installing acceptance-test
super-rentals %

The application was create with this line from the tutorial:

ember new super-rentals

The versions are:

super-rentals % ember --version
ember-cli: 2.11.1
node: 6.9.5
os: darwin x64