Docker test phase logs into docker repo

Build Environment
1

During execution of this circle job:

machine:
  timezone:
    America/Los_Angeles

  services:
    - docker

dependencies:
  pre:
    - docker login -u $ART_USERNAME -p $ART_PW -e $ART_EMAIL private-repo.com
  override:
    - docker build -t our-org/hello-world:$CIRCLE_SHA1 .

deployment:
  master:
    branch: master
    commands:
      - docker tag our-org/hello-world:latest /silintl/ecs-deploy:$CIRCLE_SHA1
      - docker push private-repo.com/silintl/ecs-deploy:$CIRCLE_SHA1'

The test section shows a login:

$ docker login -u $DOCKER_USERNAME -p $DOCKER_PW private-repo.com

Why?