PHPunit through docker : Could not translate host name to address

Hello there !

I'm trying to set up PhpStorm to run my Phpunit tests on my Docker container.

I have 3 containers : webapi (where my PHP code is) and db. Now first of all, my current architecture runs just fine in general and especially when I run tests in remote CLI, so i'm already certain my issue is how to configure PhpStorm.

I've set up a remote interpreter on my webapi container and mapped my folders. My unit tests work. But when I run my functional tests (which need to reach the DB), I get this :
Doctrine\DBAL\Exception\ConnectionException : An exception occurred in driver: SQLSTATE[08006] [7] could not translate host name "db" to address: Name or service not known

I went into my container settings. I've found a "Links" section. I've added my other container inside, then when I try to run my tests, I get this :

16:09 Error running 'tests': Cannot link to /db, as it does not belong to the default network. To fix it change project interpreter or check settings.

I assume it comes from how PhpStorm starts the container, but I can't figure how to set it up to recognize my db container.

Any idea ?