HA-008 HA-009: add discovery and history pipeline

Closes #17

Closes #18

tests/api/test_entities.py

@@ -1,8 +1,11 @@
 from collections.abc import Sequence
+from datetime import datetime
 
 from fastapi.testclient import TestClient
 
 from app.ha.exceptions import HaTimeoutError
+from app.ha.discovery import DiscoveredEntity, EntityRole
+from app.ha.history import EntityHistorySeries, NumericHistoryPoint
 from app.ha.models import HaEntitySummary
 from app.ha.reader import HaReader
 from app.main import app
@@ -15,6 +18,38 @@ class FakeHaReader(HaReader):
     def read_entities(self) -> Sequence[HaEntitySummary]:
         return [HaEntitySummary(entity_id="sensor.temperature", domain="sensor")]
 
+    def discover(
+        self,
+        domains: set[str] | None = None,
+        learnable: bool | None = None,
+    ) -> Sequence[DiscoveredEntity]:
+        result = DiscoveredEntity(
+            entity_id="sensor.temperature",
+            domain="sensor",
+            device_class="temperature",
+            role=EntityRole.MEASUREMENT,
+            learnable=True,
+            reason="Numerischer Messsensor für Zeitreihen und Training.",
+        )
+        if domains and result.domain not in domains:
+            return []
+        if learnable is not None and result.learnable is not learnable:
+            return []
+        return [result]
+
+    def read_history(
+        self,
+        entity_ids: list[str],
+        start_time: datetime,
+        end_time: datetime,
+    ) -> Sequence[EntityHistorySeries]:
+        return [
+            EntityHistorySeries(
+                entity_id=entity_ids[0],
+                points=[NumericHistoryPoint(timestamp=start_time, value=21.5)],
+            )
+        ]
+
 
 class TimeoutHaReader(HaReader):
     def __init__(self) -> None:
@@ -59,3 +94,44 @@ def test_entities_maps_ha_errors_without_leaking_details() -> None:
         response = client.get("/v1/entities")
     assert response.status_code == 504
     assert response.json() == {"detail": "Home Assistant request timed out."}
+
+
+def test_discovery_filters_entities() -> None:
+    with TestClient(app) as client:
+        app.state.ha_reader = FakeHaReader()
+        response = client.get("/v1/discovery?domain=sensor&learnable=true")
+
+    assert response.status_code == 200
+    assert response.json() == [
+        {
+            "entity_id": "sensor.temperature",
+            "domain": "sensor",
+            "device_class": "temperature",
+            "state_class": None,
+            "unit_of_measurement": None,
+            "role": "measurement",
+            "learnable": True,
+            "reason": "Numerischer Messsensor für Zeitreihen und Training.",
+        }
+    ]
+
+
+def test_history_returns_normalized_series() -> None:
+    with TestClient(app) as client:
+        app.state.ha_reader = FakeHaReader()
+        response = client.get(
+            "/v1/history",
+            params=[
+                ("entity_id", "sensor.temperature"),
+                ("start_time", "2026-06-01T00:00:00Z"),
+                ("end_time", "2026-06-02T00:00:00Z"),
+            ],
+        )
+
+    assert response.status_code == 200
+    assert response.json() == [
+        {
+            "entity_id": "sensor.temperature",
+            "points": [{"timestamp": "2026-06-01T00:00:00Z", "value": 21.5}],
+        }
+    ]