[TwigComponents] Provide example of how to write a test

[tacman]

Is there an example of how to test a component?

That is, a functional test? Unit test? I assume it'll be something like inject twig, create a twig snippet, then render? Or is there a way to invoke the component class directly?

An example with the simple AlertComponent would be helpful.

Thanks.

[kbond]

Did you take a look at #821?

[tacman]

EXACTLY what I was looking for. Thanks!!