.travis.yml

#https://docs.travis-ci.com/user/docker/
language: ruby

services:
  - docker

env:
  global:
    # https://graysonkoonce.com/getting-the-current-branch-name-during-a-pull-request-in-travis-ci/
    - export BRANCH=$(if [ "$TRAVIS_PULL_REQUEST" == "false" ]; then echo $TRAVIS_BRANCH; else echo $TRAVIS_PULL_REQUEST_BRANCH; fi)
    - export SLUG=$(if [ "$TRAVIS_PULL_REQUEST" == "false" ]; then echo $TRAVIS_REPO_SLUG; else echo $TRAVIS_PULL_REQUEST_SLUG; fi)

script:
  - echo BRANCH="$BRANCH", SLUG="$SLUG"
  - git clone --depth 1 --branch $BRANCH https://github.com/$SLUG.git repo
  - docker build --tag test repo
  - docker run -v $(pwd)/:/data/ test repo/.travis.yml