Laravel 5.8 PHPUnit在内存测试中无法正常工作

I know this has been asked over and over, and duplicates exist. However, I still have the question.

Well, the title says it. I'm developing an app and taking the TDD approach. For PHPUnit I want it to do all the database actions in an in-memory database, as has been described many times on tutorial pages. However, I don't seem to get it to work as all test runs result in new records in the actual database. I've tried php artisan cache:clear after each alteration I made, but without success. What am I doing wrong?

PHPUnit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit backupGlobals="false"
         backupStaticAttributes="false"
         bootstrap="vendor/autoload.php"
         colors="true"
         convertErrorsToExceptions="true"
         convertNoticesToExceptions="true"
         convertWarningsToExceptions="true"
         processIsolation="false"
         stopOnFailure="false">
    <testsuites>
        <testsuite name="Unit">
            <directory suffix="Test.php">./tests/Unit</directory>
        </testsuite>

        <testsuite name="Feature">
            <directory suffix="Test.php">./tests/Feature</directory>
        </testsuite>
    </testsuites>
    <filter>
        <whitelist processUncoveredFilesFromWhitelist="true">
            <directory suffix=".php">./app</directory>
        </whitelist>
    </filter>
    <php>
        <server name="APP_ENV" value="testing"/>
        <server name="BCRYPT_ROUNDS" value="4"/>
        <server name="CACHE_DRIVER" value="array"/>
        <server name="MAIL_DRIVER" value="array"/>
        <server name="QUEUE_CONNECTION" value="sync"/>
        <server name="SESSION_DRIVER" value="array"/>
        <server name="DB_CONNECTION" value="sqlite_testing"/>
        <server name="API_DEBUG" value="false"/>
        <server name="memory_limit" value="512M" />
    </php>
</phpunit>

.env.testing

APP_NAME=Laravel
APP_ENV=testing
APP_KEY=base64:same-as-.env
APP_DEBUG=true
APP_URL=http://localhost

LOG_CHANNEL=stack

DB_CONNECTION=sqlite_testing
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=:memory:
DB_USERNAME=
DB_PASSWORD=

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

REDIS_HOST=127.0.0.1
REDIS_PASSWORD=null
REDIS_PORT=6379

MAIL_DRIVER=smtp
MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=username
MAIL_PASSWORD=pwd
MAIL_ENCRYPTION=tls

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

PUSHER_APP_ID=
PUSHER_APP_KEY=
PUSHER_APP_SECRET=
PUSHER_APP_CLUSTER=mt1

MIX_PUSHER_APP_KEY="${PUSHER_APP_KEY}"
MIX_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"

config/database.php

'connections' => [

        ...

        'sqlite_testing' => [
            'driver' => 'sqlite',
            'database' => ':memory:',
            'prefix' => ''
        ],

Solved All I needed to do was a php artisan config:clear, after that it worked.