On travis-ci.org "not in a Meteor project directory"

I have set up a GitHub repository with Travis CI integration for my Meteor project. When I push a new build, the CI test fails with the following reason:

> PackageName@ test /home/travis/build/packagename/gitname
> meteor test --once --driver-package meteortesting:mocha

test: You’re not in a Meteor project directory.

Here’s my .travis.yml file:

language: node_js
- "12.16"
# Install meteor
- curl https://install.meteor.com | /bin/sh
# Add meteor to path (instead of asking for sudo in the Travis container)
# We can then use the faster container infrastructure - http://docs.travis-ci.com/user/workers/container-based-infrastructure/
- export PATH=$HOME/.meteor:$PATH
- npm install -g spacejam

- node_modules

How should I edit my travis.yml file so that the tests can be run correctly?