compile and test php on circleci using redhat openshift s2i image that matches OCP builds

config.yml

version: 2.0
jobs:
  build:
    docker:
      - image: "registry.access.redhat.com/rhscl/php-71-rhel7:latest"
    steps:
      - checkout:
          path: /tmp/src/

      # Download and cache dependencies
      - restore_cache:
          keys:
          - rhel7-dependencies-{{ checksum "/tmp/src/composer.json" }}

      - run:
          name: s2i assemble
          command: /usr/libexec/s2i/assemble

      - save_cache:
          paths:
            - ./vendor
          key: rhel7-dependencies-{{ checksum "composer.json" }}
          
      # run tests!
      - run: vendor/bin/phpunit --configuration phpunit.xml

Note that s2i expects you to checkout into /tmp/src ten runs /usr/libexec/s2i/assemble. The other bits about caching the ./vendor folder is circleci.com specific to speed up your builds.