I see what you mean, I guess the best and only way to do that would be to write integration like tests with something like Cypress, as you could with any web-app.
If you want to verify that it works how you want vs how it's setup to work, then you would be better leaning on existing tools that can do that.
My point about not needing to test it was about the implicit trust you would put in a platform like this, just like you would trust that a library you import behaves how it describes. It's not expected that you should write unit tests and integration tests to verify the behaviour of an external library
