Adding new databse for testing only

I am trying to add a new databse to my project in order to use it for testing, and to have the "official" database used for developers to work on it. I'd like both databases to be accessed within the same PHPMyAdmin, but I do not know how to configure my project for that. I've seen some people on the web using another .env file, something like .env.testing, but I've not been able to go on with all the configuration with docker and php unit.

Does someone know any tutorial for that or is able to help me?

My configs bellow:

.env file

APP_NAME=Biglietto
APP_ENV=local
APP_KEY=base64:LZZnP9ldEbLWLGD6V3LBtdikL9hyxHpoybWlLhBs0j0=
APP_DEBUG=true
APP_URL=http://localhost

LOG_CHANNEL=stack
LOG_DEPRECATIONS_CHANNEL=null
LOG_LEVEL=debug

DB_CONNECTION=mysql
DB_HOST=mysql_biglietto
DB_PORT=3306
DB_DATABASE=biglietto
DB_USERNAME=root
DB_PASSWORD=123456

BROADCAST_DRIVER=log
CACHE_DRIVER=file
FILESYSTEM_DISK=local
QUEUE_CONNECTION=sync
SESSION_DRIVER=file
SESSION_LIFETIME=120

MEMCACHED_HOST=127.0.0.1

REDIS_HOST=127.0.0.1
REDIS_PASSWORD=null
REDIS_PORT=6379

MAIL_MAILER=smtp
MAIL_HOST=mailhog
MAIL_PORT=1025
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null
MAIL_FROM_ADDRESS="[email protected]"
MAIL_FROM_NAME="${APP_NAME}"

AWS_ACCESS_KEY_ID=
AWS_SECRET_ACCESS_KEY=
AWS_DEFAULT_REGION=us-east-1
AWS_BUCKET=
AWS_USE_PATH_STYLE_ENDPOINT=false

PUSHER_APP_ID=
PUSHER_APP_KEY=
PUSHER_APP_SECRET=
PUSHER_HOST=
PUSHER_PORT=443
PUSHER_SCHEME=https
PUSHER_APP_CLUSTER=mt1

VITE_PUSHER_APP_KEY="${PUSHER_APP_KEY}"
VITE_PUSHER_HOST="${PUSHER_HOST}"
VITE_PUSHER_PORT="${PUSHER_PORT}"
VITE_PUSHER_SCHEME="${PUSHER_SCHEME}"
VITE_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"

docker-compose.yml

version: "3.3"
services:
  biglietto:
    build:
      context: .
      dockerfile: ./devops/Dockerfile.local
    ports:
      - 80:8000
    volumes:
      - ./:/var/www/html
    networks:
      - biglietto
    tty: true
    container_name: biglietto  
  mysql_biglietto:
    image: mariadb:10.3
    entrypoint: docker-entrypoint.sh --sql-mode='STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,TRADITIONAL,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION'
    ports:
      - 3306:3306
    networks:
      - biglietto
    environment:
      - MYSQL_ROOT_PASSWORD=123456
      - MYSQL_USER=user
      - MYSQL_PASSWORD=123456
      - MYSQL_DATABASE=biglietto
    container_name: mysql_biglietto
  phpmyadmin_biglietto:
    image: phpmyadmin/phpmyadmin
    ports:
      - 8181:80
    networks:
      - biglietto
    environment:
      PMA_HOST: mysql_biglietto
      UPLOAD_LIMIT: 300M
    container_name: phpmyadmin_biglietto
networks:
  biglietto:
    external:
      name: biglietto_network

phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
         bootstrap="vendor/autoload.php"
         colors="true"
>
    <testsuites>
        <testsuite name="Unit">
            <directory suffix="Test.php">./tests/Unit</directory>
        </testsuite>
        <testsuite name="Feature">
            <directory suffix="Test.php">./tests/Feature</directory>
        </testsuite>
    </testsuites>
    <coverage processUncoveredFiles="true">
        <include>
            <directory suffix=".php">./app</directory>
        </include>
    </coverage>
    <php>
        <env name="APP_ENV" value="testing"/>
        <env name="BCRYPT_ROUNDS" value="4"/>
        <env name="CACHE_DRIVER" value="array"/>
        <env name="MAIL_MAILER" value="array"/>
        <env name="QUEUE_CONNECTION" value="sync"/>
        <env name="SESSION_DRIVER" value="array"/>
        <env name="TELESCOPE_ENABLED" value="false"/>
        <!-- <env name="DB_CONNECTION" value="mysql"/> -->
        <!-- <env name="DB_DATABASE" value=":memory:"/> -->
    </php>
</phpunit>