Travis CI (https://travis-ci.org/) is a distributed build server used to build and test software projects hosted on GitHub. Travis supports open source projects with no charge.

The configuration of Travis CI is done using a file named .travis.yaml. The content of this file is structured using different keywords, including:

• language: Project language, that is, java, node_js, ruby, python, or php among others (the complete list is available on https://docs.travis-ci.com/user/languages/).
• sudo: Flag value to set if superuser privileges are needed (for example to install Ubuntu packages).
• dist: Builds can be executed on Linux environments (Ubuntu Precise 12.04 or Ubuntu Trusty 14.04).
• addons: Declarative shortcuts to basic operations of the apt-get commands.
• install: First part of the Travis build life cycle, in which the installation of the required dependencies is done. This part can be optionally initiated using before_install.
• script: Actual execution of the build. This phase can be optionally surrounded by before_script and after_script.
• deploy: Finally, the deployment of the build can be optionally made in this phase. This stage has its own life cycle controlled with before_deploy and after_deploy.

The following snippet shows an example of .travis.yaml:

language: java
sudo: false
dist: trusty

addons:
    firefox: latest
    apt:
        packages:
            - google-chrome-stable
    sonarcloud:
        organization: "bonigarcia-github"
        token:
            secure: "encripted-token"

before_script:
    - export DISPLAY=:99.0
    - sh -e /etc/init.d/xvfb start &
    - sleep 3

script:
    - mvn test sonar:sonar
    - bash <(curl -s https://codecov.io/bash)

Travis CI provides a web dashboard in which we can check the status of the current and past build generated in the projects using Travis CI of our GitHub account: