test(backend): exerce AlertSeverity comme enum plutot qu'une chaine dans les tests alerts

Le filtre severity passait par une chaine brute dans les tests, sans jamais
exercer le trajet reel AlertSeverity (enum) -> SQLAlchemy -> PostgreSQL.

apps/backend/tests/api/test_alerts.py

@@ -10,6 +10,7 @@ from app.api.deps import get_alert_service, get_current_principal
 from app.core.principal import Principal
 from app.core.roles import AccountKind, Role
 from app.models.energy import Alert
+from app.schemas.alert import AlertSeverity
 
 
 def principal(role: Role = Role.LECTEUR) -> Principal:
@@ -112,7 +113,7 @@ async def test_list_alerts_transmits_the_severity_filter(
 
     await client.get("/api/v1/alerts?severity=critical")
 
-    assert service.appels == [(None, "critical")]
+    assert service.appels == [(None, AlertSeverity.CRITICAL)]
 
 
 async def test_list_alerts_returns_422_for_an_unknown_severity(

apps/backend/tests/repositories/test_alert.py

@@ -6,6 +6,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.energy import Alert
 from app.repositories.alert import AlertRepository
+from app.schemas.alert import AlertSeverity
 from tests.repositories.test_site import creer as creer_site
 from tests.repositories.test_site import identifiant as identifiant_site
 
@@ -73,7 +74,7 @@ async def test_list_all_filters_by_severity(session: AsyncSession) -> None:
     voulue = await creer_alerte(session, site_id=site.site_id, severity="critical")
     await creer_alerte(session, site_id=site.site_id, severity="low")
 
-    alertes = await depot.list_all(severity="critical")
+    alertes = await depot.list_all(severity=AlertSeverity.CRITICAL)
     identifiants = [a.alert_id for a in alertes]
     await session.rollback()