Gitlab CI test stage

docker-compose-testing.yml

version: '3.5'
services:
  testing_server:
    depends_on:
      - testing_database
    environment:
     - A_BUNCH_OF_VARIABLES=${A_BUNCH_OF_VARIABLES}
    image: ${SERVER_TESTING_IMAGE_NAME}:${COMMIT_REF}
    container_name: testing_server
    build:
      context: ../..
      dockerfile: ./server/config/Dockerfile
      target: testing

newCI.yml

test_server:
  tags:
    - mytag
  stage: test
  image: docker:19.03.12
  services:
    - docker:19.03.12-dind
  before_script:
    - apk update && apk add --no-cache curl
    - curl -L --fail https://github.com/docker/compose/releases/download/1.28.0/run.sh -o /usr/local/bin/docker-compose
    - chmod +x /usr/local/bin/docker-compose
    - echo "$CI_JOB_TOKEN" | docker login -u $CI_REGISTRY_USER --password-stdin $GITLAB_REGISTRY
  script:
    - cd Application/server
    - docker pull $SERVER_TESTING_IMAGE_NAME:latest || true
    - docker build --cache-from $SERVER_TESTING_IMAGE_NAME:latest -t $SERVER_TESTING_IMAGE_NAME:$COMMIT_REF -t $SERVER_TESTING_IMAGE_NAME:latest -f config/Dockerfile --target=testing ..
    - docker-compose --project-directory . -f ./config/docker-compose-testing.yml config
    - docker-compose --project-directory . -f ./config/docker-compose-testing.yml build
    - docker-compose --project-directory . -f ./config/docker-compose-testing.yml up --exit-code-from testing_server
    - docker-compose --project-directory . -f ./config/docker-compose-testing.yml down -v
    - docker tag $SERVER_TESTING_IMAGE_NAME:latest $SERVER_TESTING_IMAGE_NAME:$COMMIT_REF
    - docker push $SERVER_TESTING_IMAGE_NAME:$COMMIT_REF
    - docker push $SERVER_TESTING_IMAGE_NAME:latest

originalCI.yml

test_server:
  tags:
    - mytag
  stage: test
  image: docker/compose:1.25.5
  services:
    - docker:18.09.7-dind
  before_script:
    - echo "$CI_REGISTRY_PASSWORD" | docker login -u $CI_REGISTRY_USER --password-stdin $GITLAB_REGISTRY
  script:
    - cd Application/server
    - docker pull $SERVER_TESTING_IMAGE_NAME:latest || true
    - docker build -t $SERVER_TESTING_IMAGE_NAME:$COMMIT_REF -t $SERVER_TESTING_IMAGE_NAME:latest -f config/Dockerfile --target=testing .
    - docker-compose -f ./config/docker-compose-testing.yml build
    - docker-compose -f ./config/docker-compose-testing.yml up --exit-code-from testing_server
    - docker-compose -f ./config/docker-compose-testing.yml down -v
    - docker tag $SERVER_TESTING_IMAGE_NAME:latest $SERVER_TESTING_IMAGE_NAME:$COMMIT_REF
    - docker push $SERVER_TESTING_IMAGE_NAME:$COMMIT_REF
    - docker push $SERVER_TESTING_IMAGE_NAME:latest