Installs the latest Firefox and geckodriver on CircleCI. Works with `selenium-webdriver-3.4.4`

circle.yml

dependencies:
  pre:
    - pip install mozdownload mozinstall
    - mozdownload --version latest --destination firefox.tar.bz2
    - mozinstall firefox.tar.bz2
    - wget -O geckodriver.tar.gz https://github.com/mozilla/geckodriver/releases/download/v0.18.0/geckodriver-v0.18.0-linux64.tar.gz
    - gunzip -c geckodriver.tar.gz | tar xopf -
    - chmod +x geckodriver && mv geckodriver /home/ubuntu/bin/
machine:
  environment:
    DATABASE_URL: postgres://ubuntu:@127.0.0.1:5432/circle_test
    PATH: "${HOME}/${CIRCLE_PROJECT_REPONAME}/firefox:${PATH}"
test:
  override:
    - bundle exec rspec -r rspec_junit_formatter --format RspecJunitFormatter -o $CIRCLE_TEST_REPORTS/rspec/junit.xml
  post:
    - bundle exec rubocop