docker-compose.test.yml

version: '2'

services:
  test:
    environment:
      ENV_TWO: 'overridden'

docker-compose.yml

version: '2'

services:
  test:
    image: spatialnetworks/alpine
    command: sh e.sh
    environment:
      ENV_ONE: 'not-overridden'
      ENV_TWO: 'not-overridden'
    volumes:
      - ./:/app

e.sh

echo $ENV_ONE
echo $ENV_TWO

terminal.log

  docker-compose -f docker-compose.yml -f docker-compose.test.yml run --rm test
not-overridden
overridden