perf: view_tryout, une requete par lot au lieu d une par ligne

PERF-001, la page la plus consultee de l application. Quatre boucles
posaient une requete par ligne :

  User.query.get()          par inscription
  Evaluation.query          par joueur inscrit, pour savoir si ce coach
                            l avait deja evalue
  TeamMember.query          par equipe
  User.query.get()          par membre d equipe

Plus, sur chaque match de type player_vs_player, deux interrogations
supplementaires de la relation dynamique `participants` pour trier par
camp -- alors que la liste complete venait d etre chargee douze lignes plus
haut.

Toutes remplacees par un chargement groupe. Les evaluations de ce coach
sont deduites de la liste `evaluations` deja en memoire, pas redemandees.

Mesure, sur un tryout de 10 inscrits, 2 equipes et 1 match :
34 requetes avant, 12 apres. Le test fixe un budget de 25, volontairement
large -- il ne peut que baisser, et il echoue sur le code d avant.

_users_by_id() est le helper partage par les trois chargements ; une ligne
absente est simplement absente du dictionnaire, ce que faisait deja un
get() renvoyant None.

Un second test verifie que les dix joueurs apparaissent toujours sur la
page : une requete groupee qui perd des lignes est le risque reel ici, pas
l erreur bruyante.

Co-Authored-By: Claude Opus 5 <[email protected]>

tests/test_query_shape.py

@@ -231,3 +231,84 @@ class TestPendingEvaluations:
             db.session.commit()
 
         assert self._pending(client) == 1
+
+
+class TestViewTryout:
+    """PERF-001 — the most-visited page in the application ran one query
+    per registration, one per player evaluated, one per team, and one per
+    team member. Thirty registrants and four teams put it past a hundred
+    round trips for a single render."""
+
+    @pytest.fixture
+    def populated_tryout(self, app, make_user):
+        """A tryout with ten registrants split across two teams."""
+        from app.models import Match, MatchParticipant, Team, TeamMember
+
+        admin_id = make_user('admin')
+        player_ids = [make_user('player') for _ in range(10)]
+
+        with app.app_context():
+            tryout = Tryout(
+                title='Spring', game='Valorant', date=date(2030, 3, 1), created_by=admin_id
+            )
+            db.session.add(tryout)
+            db.session.flush()
+
+            for player_id in player_ids:
+                db.session.add(TryoutRegistration(tryout_id=tryout.id, player_id=player_id))
+
+            for index in range(2):
+                team = Team(tryout_id=tryout.id, name=f'Team {index}', created_by=admin_id)
+                db.session.add(team)
+                db.session.flush()
+                for player_id in player_ids[index * 5 : (index + 1) * 5]:
+                    db.session.add(TeamMember(team_id=team.id, player_id=player_id))
+
+            match = Match(
+                tryout_id=tryout.id,
+                title='Scrim',
+                date=date(2030, 3, 2),
+                match_type='player_vs_player',
+                created_by=admin_id,
+            )
+            db.session.add(match)
+            db.session.flush()
+            for side, player_id in enumerate(player_ids[:4]):
+                db.session.add(
+                    MatchParticipant(
+                        match_id=match.id, player_id=player_id, team_side=(side % 2) + 1
+                    )
+                )
+            db.session.commit()
+            return tryout.id, admin_id, player_ids
+
+    def test_the_page_still_shows_everyone(self, app, client, as_role, populated_tryout):
+        tryout_id, _admin_id, player_ids = populated_tryout
+        as_role('admin')
+
+        body = client.get(f'/tryouts/{tryout_id}').get_data(as_text=True)
+
+        with app.app_context():
+            usernames = [db.session.get(User, pid).username for pid in player_ids]
+        for username in usernames:
+            assert username in body, f'{username} is missing from the page'
+
+    def test_the_cost_does_not_grow_with_the_squad(
+        self, app, client, as_role, populated_tryout, count_queries
+    ):
+        tryout_id, _admin_id, _player_ids = populated_tryout
+        as_role('admin')
+
+        with app.app_context():
+            counter = count_queries()
+            try:
+                response = client.get(f'/tryouts/{tryout_id}')
+            finally:
+                counter.stop()
+
+        assert response.status_code == 200
+        # Ten registrants, two teams of five, one match of four. The old
+        # shape spent more than thirty queries on those rows alone; the
+        # budget here is deliberately loose but far below that, and it can
+        # only be lowered.
+        assert 1 <= counter.total <= 25, f'{counter.total} SELECTs to render one tryout'