feat: vue détail d'un site (#51)

Ajoute la page de détail d'un site (fiche, mesure instantanée, jauge de
consommation, historique) en remplacement du placeholder. Les champs
null sont affichés explicitement avec leur raison plutôt que masqués.

Ajoute l'endpoint GET /sites/{id}/current côté backend, qui retourne la
dernière mesure connue d'un site sans filtre temporel, conformément au
contrat de l'issue.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012i5NteMLRZgfTAKB5GD37X

apps/backend/tests/api/test_sites.py

@@ -1,14 +1,15 @@
 from collections.abc import Callable, Iterator
+from datetime import UTC, datetime
 from uuid import uuid4
 
 import pytest
 from fastapi import FastAPI
 from httpx import AsyncClient
 
-from app.api.deps import get_current_principal, get_site_service
+from app.api.deps import get_current_principal, get_reading_service, get_site_service
 from app.core.principal import Principal
 from app.core.roles import AccountKind, Role
-from app.models.energy import Site
+from app.models.energy import Reading, Site
 from app.services.site import SiteNotFoundError
 
 
@@ -47,6 +48,26 @@ class FauxService:
         return self.site
 
 
+def reading(site_id: str = "site-1") -> Reading:
+    return Reading(
+        reading_id=1,
+        site_id=site_id,
+        timestamp=datetime(2026, 9, 16, tzinfo=UTC),
+        source="csv",
+        consumption_kw=42.5,
+        data_quality="good",
+        raw_data={},
+    )
+
+
+class FauxReadingService:
+    def __init__(self, derniere: Reading | None) -> None:
+        self._derniere = derniere
+
+    async def get_latest(self, site_id: str) -> Reading | None:
+        return self._derniere
+
+
 @pytest.fixture
 def lecteur_connecte(app: FastAPI) -> Iterator[None]:
     app.dependency_overrides[get_current_principal] = lambda: principal()
@@ -67,6 +88,19 @@ def servi(
     app.dependency_overrides.pop(get_site_service, None)
 
 
+@pytest.fixture
+def readings_servis(
+    app: FastAPI, lecteur_connecte: None
+) -> Iterator[Callable[[Reading | None], FauxReadingService]]:
+    def installe(derniere: Reading | None) -> FauxReadingService:
+        service = FauxReadingService(derniere)
+        app.dependency_overrides[get_reading_service] = lambda: service
+        return service
+
+    yield installe
+    app.dependency_overrides.pop(get_reading_service, None)
+
+
 async def test_list_sites_returns_the_sites(
     servi: Callable[..., FauxService], client: AsyncClient
 ) -> None:
@@ -139,3 +173,45 @@ async def test_get_site_returns_404_when_the_session_finds_nothing(
     response = await client.get("/api/v1/sites/inconnu")
 
     assert response.status_code == 404
+
+
+async def test_get_current_returns_the_latest_reading_regardless_of_its_age(
+    servi: Callable[..., FauxService],
+    readings_servis: Callable[[Reading | None], FauxReadingService],
+    client: AsyncClient,
+) -> None:
+    servi()
+    readings_servis(reading())
+
+    response = await client.get("/api/v1/sites/site-1/current")
+
+    assert response.status_code == 200
+    corps = response.json()
+    assert corps["consumption_kw"] == 42.5
+
+
+async def test_get_current_returns_null_when_the_site_has_no_reading(
+    servi: Callable[..., FauxService],
+    readings_servis: Callable[[Reading | None], FauxReadingService],
+    client: AsyncClient,
+) -> None:
+    servi()
+    readings_servis(None)
+
+    response = await client.get("/api/v1/sites/site-1/current")
+
+    assert response.status_code == 200
+    assert response.json() is None
+
+
+async def test_get_current_returns_404_for_an_unknown_site(
+    servi: Callable[..., FauxService],
+    readings_servis: Callable[[Reading | None], FauxReadingService],
+    client: AsyncClient,
+) -> None:
+    servi(SiteNotFoundError("site-inconnu"))
+    readings_servis(None)
+
+    response = await client.get("/api/v1/sites/site-inconnu/current")
+
+    assert response.status_code == 404

apps/backend/tests/repositories/test_reading.py

@@ -88,6 +88,31 @@ async def test_latest_by_site_returns_one_row_per_site(session: AsyncSession) ->
     assert identifiants == {premier, second}
 
 
+async def test_latest_for_site_ignores_how_old_the_reading_is(session: AsyncSession) -> None:
+    site = await creer_site(session)
+    depot = ReadingRepository(session)
+    await creer_lecture(session, site_id=site.site_id, timestamp=datetime(2024, 1, 1, tzinfo=UTC))
+    recente = await creer_lecture(
+        session, site_id=site.site_id, timestamp=datetime(2024, 12, 31, tzinfo=UTC)
+    )
+
+    resultat = await depot.latest_for_site(site.site_id)
+    await session.rollback()
+
+    assert resultat is not None
+    assert resultat.reading_id == recente.reading_id
+
+
+async def test_latest_for_site_returns_none_when_the_site_has_no_reading(
+    session: AsyncSession,
+) -> None:
+    depot = ReadingRepository(session)
+
+    resultat = await depot.latest_for_site(identifiant_site())
+
+    assert resultat is None
+
+
 async def test_list_history_orders_the_readings_by_timestamp_descending(
     session: AsyncSession,
 ) -> None:

apps/backend/tests/services/test_reading.py

@@ -28,6 +28,11 @@ class FakeRepository:
     def __init__(self, readings: list[Reading]) -> None:
         self._readings = readings
         self.appels: list[tuple[str | None, datetime, datetime, int, int]] = []
+        self.site_interroge: str | None = None
+
+    async def latest_for_site(self, site_id: str) -> Reading | None:
+        self.site_interroge = site_id
+        return self._readings[0] if self._readings else None
 
     async def list_history(
         self,
@@ -42,6 +47,25 @@ class FakeRepository:
         return self._readings
 
 
+async def test_get_latest_relays_the_repository_reading() -> None:
+    depot = FakeRepository([reading(1)])
+    service = ReadingService(readings=depot)
+
+    lecture = await service.get_latest("site-1")
+
+    assert lecture is not None
+    assert lecture.reading_id == 1
+    assert depot.site_interroge == "site-1"
+
+
+async def test_get_latest_returns_none_when_the_site_has_no_reading() -> None:
+    service = ReadingService(readings=FakeRepository([]))
+
+    lecture = await service.get_latest("site-1")
+
+    assert lecture is None
+
+
 async def test_list_history_returns_the_repository_readings() -> None:
     service = ReadingService(readings=FakeRepository([reading(1), reading(2)]))