Docker-compose to create lamp with phpunit

I'm trying to use docker-compose to create a LAMP environment along with phpunit to run TDD php and what I want to do is this:

• run a mysql image 5;

• run an image phpunit 5;

• run a php 5.6 image so that it communicates with the other images;

My docker-compose looks like this:

version: '2'

services:
  mysql:
    image: mysql:5
    expose:
      - "3306"
    environment:
      MYSQL_ROOT_PASSWORD: 12345
      MYSQL_DATABASE: lamp-teste

  php-unit:
      image: phpunit/phpunit:5.7.12

  php-5.6:
    image: php:5.6
    ports:
      - 8080:80
    volumes:
      - ./log/apache2/error.log:/var/log/apache2/error.log
      - ./log/apache2/access.log:/var/log/apache2/access.log
      - ./html:/var/www/html
    environment:
      WORDPRESS_DB_HOST: mysql
      WORDPRESS_DB_USER: root
    depends_on:
      - mysql
      - php-unit

After running the file with the docker-compose up -d command this appears:

Recreating dockerlampteste_mysql_1 ... 
Recreating dockerlampteste_php-unit_1 ... 
Recreating dockerlampteste_php-unit_1
Recreating dockerlampteste_mysql_1 ... done
Recreating dockerlampteste_php-5.6_1 ... 
Recreating dockerlampteste_php-5.6_1 ... done

And when you run the "docker-compose ps" command this appears:

Name                         Command             State     Ports  
----------------------------------------------------------------------
dockerlampteste_mysql_1      docker-entrypoint.sh mysqld     Up       
3306/tcp
dockerlampteste_php-5.6_1    docker-php-entrypoint php -a    Exit 0           

dockerlampteste_php-unit_1   /usr/local/bin/phpunit --help   Exit 0 

And when you run the command "docker ps" it appears that only the mysql image is running.