In Laravel, it's easy to set environment variables that are specific to your testing environment. Just edit your phpunit.xml file and set them as entries in the block:

<php>
    <env name="APP_ENV" value="testing"/>
    <env name="CACHE_DRIVER" value="array"/>
    <env name="SESSION_DRIVER" value="array"/>
    <env name="QUEUE_DRIVER" value="sync"/>
    <env name="DB_DATABASE" value=":memory:"/>
    <env name="DB_CONNECTION" value="sqlite"/>
    <env name="TWILIO_FROM_NUMBER" value="+15005550006"/>
</php>

But what if you find yourself needing to exclude these values from version control?