Php container unable to talk to mysql

My php container is unable to talk to the mysql container using the hostname. I am getting this error

php_network_getaddresses: getaddrinfo failed: Name or service not known

This is my gitlab-ci.yml

# This file is a template, and might need editing before it works on your project.
# Select image from
image: php:7.1.17

# Select what we should cache between builds
  - vendor/

- apt-get update -yqq
- apt-get install -yqq git libmcrypt-dev libpq-dev libcurl4-gnutls-dev libicu-dev libvpx-dev libjpeg-dev libpng-dev libxpm-dev zlib1g-dev libfreetype6-dev libxml2-dev libexpat1-dev libbz2-dev libgmp3-dev libldap2-dev unixodbc-dev libsqlite3-dev libaspell-dev libsnmp-dev libpcre3-dev libtidy-dev
# Install PHP extensions
- docker-php-ext-install mbstring mcrypt curl json intl gd xml zip bz2 opcache pdo_mysql
# Install & enable Xdebug for code coverage reports
- pecl install xdebug
- docker-php-ext-enable xdebug
# Install and run Composer
- curl -sS | php
- php composer.phar install

# Bring in any services we need
# See for examples.
- name: mysql:5.7
  alias: database
  command: ["mysql", "-u", "root", "-p", "test_unittest", "<", "./test/test_unittest.sql"]

# Set any variables we need
  # Configure mysql environment variables (
  MYSQL_DATABASE: test_unittest

# Run our tests
# If Xdebug was installed you can generate a coverage report and see code coverage metrics.
vendor/bin/phpunit --configuration phpunit.xml --coverage-text --colors=never