I need to write a test that will check a local variable value inside a static function. I went through all the unittest docs but found nothing yet.
You can't. Local variables are local to the function and they cannot be accessed from the outside.
But the bigger point is that you shouldn't actually be trying to test the value of a local variable. Functions should be treated as black boxes from the outside. The are given some parameters and they return some values and/or change the external state. Those are the only things you should check for.