Part 2, Chapter 13 missing test_update_user_duplicate_email

in PUT Duplicate Email section, there is a test code but not checking duplicate email.

Are we checking to see if an email exists before updating a user?

Write a test:

def test_update_user(test_app, test_database, add_user):
~SNIP~

I bring the test test_update_user_duplicate_email from this repo.
Would you correct the Chapter 13 text?