Xcode unit tests for plugin bundles

I want to add unit tests into my application. Unfortunately currently the most functionality lives inside a plugin.

My plugin infrastructure consists of a framework with a plugin base class and some shared helper classes and resources.

Now I want to add a unit test that is able to test my plugin. I thought of creating a "testing" application that loads that bundle and redirects all calls to the loaded and initialized class.

But how do I then import the plugins class header? Are there any advices on how to unit test bundles / executables that cannot run on their own?