PHPunit testing

I writing phpunit tests for Lumen API, and for some reason framework doesn't use .env.testing configuration file for the test database.

As from Laravel 5.5 - Laravel 5.7, I used to create .env.testing file to run test seeders and phpunit tests.

.env

APP_ENV=local
APP_DEBUG=true
APP_KEY=appkey
APP_TIMEZONE=UTC

LOG_CHANNEL=stack
LOG_SLACK_WEBHOOK_URL=

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=api
DB_USERNAME=homestead
DB_PASSWORD=secret

CACHE_DRIVER=file
QUEUE_DRIVER=sync

.env.testing

APP_ENV=testing
APP_DEBUG=true
APP_KEY=appkey
APP_TIMEZONE=UTC

LOG_CHANNEL=stack
LOG_SLACK_WEBHOOK_URL=

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=api_test
DB_USERNAME=homestead
DB_PASSWORD=secret

CACHE_DRIVER=file
QUEUE_DRIVER=sync

phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit backupGlobals="false"
         backupStaticAttributes="false"
         bootstrap="bootstrap/app.php"
         colors="true"
         convertErrorsToExceptions="true"
         convertNoticesToExceptions="true"
         convertWarningsToExceptions="true"
         processIsolation="false"
         stopOnFailure="false">
    <testsuites>
        <testsuite name="Application Test Suite">
            <directory suffix="Test.php">./tests</directory>
        </testsuite>
    </testsuites>
    <filter>
        <whitelist processUncoveredFilesFromWhitelist="true">
            <directory suffix=".php">./app</directory>
        </whitelist>
    </filter>
    <php>
        <env name="APP_ENV" value="testing"/>
        <env name="CACHE_DRIVER" value="array"/>
        <env name="QUEUE_DRIVER" value="sync"/>
    </php>
</phpunit>