docker-compose.yml

version: '2'

services:
  tests-1:
    build:
      dockerfile: Dockerfile-1
      context: .
  tests-2:
    build:
      dockerfile: Dockerfile-2
      context: .

Dockerfile-1

FROM alpine

ADD helloworld-1.sh /usr/local/bin/helloworld.sh

Dockerfile-2

FROM alpine

ADD helloworld-2.sh /usr/local/bin/helloworld.sh

helloworld-1.sh

#!/bin/sh

echo "Hello world 1"

helloworld-2.sh

#!/bin/sh

echo "Hello world 2"