If you're using the RefreshDatabase trait, this is how I set up my unit tests that require a database to use an in-memory database using SQLite. Using an in-memory database simplifies our testing process and does not require us to set up additional testing databases.

Here's a quick tip on how to use an in-memory database for unit testing:

1. First, add a new connection in your /config/database.php

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

2. In your your phpunit.xml file and set this property:

<server name="DB_CONNECTION" value="sqlite_testing"/>

3. Clear config cache

Don't forget to clear configuration cache after we added our new SQLite connection above using php artisan config:cache, which will clear & re-cache your application configs.

Now, you should be able to just run your test command and use your in-memory database to run unit tests.

Happy testing 🤘