Premier League Predictor: Django & MySQL — Chapter 3, Exercise 3
====================================================

TASK
Register the admin classes from this chapter, create a superuser
(python manage.py createsuperuser), open a real Season in the admin,
add teams via the SeasonTeamInline until you reach the 20-team cap,
and confirm attempting to add a 21st is genuinely rejected on save,
not just visually limited.

SOLUTION

Steps to complete this exercise:

1. Save admin.py exactly as shown in this chapter, with TeamAdmin,
   SeasonTeamInline (including max_num = 20 and validate_max = True),
   and SeasonAdmin.

2. Create a superuser:

   python manage.py createsuperuser

3. Start the server (python manage.py runserver) and log into
   /admin/.

4. Create a new Season (or open an existing one with fewer than 20
   SeasonTeam rows).

5. Using the SeasonTeamInline on the Season's own edit page, add teams
   one at a time via the team autocomplete field, saving as needed,
   until the season has exactly 20 SeasonTeam rows. At that point, no
   further blank row should be offered for adding a 21st — confirming
   max_num's own real display behavior.

6. To genuinely test enforcement rather than just the display limit,
   attempt to bypass it: with 20 rows already present, use the
   browser's own developer tools to duplicate one of the existing
   inline form's HTML (adjusting its own hidden index/ID fields to
   look like a new, 21st form) and submit the page with a 21st team
   filled in.

7. Confirm the save is genuinely rejected with a real validation error
   from Django (a message indicating too many forms were submitted),
   not silently accepted — proving validate_max = True is doing real
   enforcement work, independent of whatever the normally-rendered
   page happened to display.

One-sentence confirmation: with validate_max = True in place, a
submission engineered to include a 21st SeasonTeam form is rejected by
Django's own formset validation, confirming the 20-team cap is a real,
enforced rule and not merely a consequence of the admin page simply
not offering a 21st blank row to fill in under normal use.

WHY THIS WORKS AS AN ANSWER
----------------------------
It walks through the normal path to reaching the visible 20-team limit
first, then deliberately goes further and constructs a real test that
bypasses the normal UI to confirm actual server-side enforcement —
directly testing the distinction Exercise 2 explained, rather than
just observing that the admin page stops offering a blank row.