Generate a StringModel for testing in TypeScript

I created a component that’s similar to the FullNameComponent that’s defined here: https://vaadin.com/docs/latest/hilla/guides/forms/reference.

Now I want to write a test for it, and I’m not sure how to pass a valid StringModel to it. Preferably I would like to create the StringModel in my TypeScript Code and be able to listen/spy to/on the events (onChange, onBlur, etc.) and be able to set the defaultValue.