How to test Angular's output signal?

I have an output signal in my component like this:

updatedBook = output<Book>();
...
updateBook(changedBook: Book){
this.updatedBook.emit(changedBook);
}


In the template I have a binding like this:

<my-component
(updatedBook)="onBookUpdate($event)"
></my-component>


And in the parent component I use the emitted value like this:

onBookUpdate(updatedBook: Book) {
this.book = Book;
}


How can I write a unit test for it? I would like to verify that the updatedBook.emit() was called.

Continue reading...