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

Closes #17

Closes #18

tests/ha/test_history.py

@@ -0,0 +1,92 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+
+import pytest
+
+from app.ha.exceptions import HaUnexpectedPayloadError
+from app.ha.history import normalize_history_payload
+
+
+def test_normalize_history_payload_groups_and_sorts_numeric_states() -> None:
+    payload = [
+        [
+            {
+                "entity_id": "sensor.temperature",
+                "state": "22.5",
+                "last_changed": "2026-06-01T12:15:00+00:00",
+            },
+            {
+                "state": "21.0",
+                "last_changed": "2026-06-01T12:00:00Z",
+            },
+        ],
+        [
+            {
+                "entity_id": "sensor.humidity",
+                "state": 45,
+                "last_updated": "2026-06-01T12:00:00+00:00",
+            }
+        ],
+    ]
+
+    result = normalize_history_payload(payload)
+
+    assert [series.entity_id for series in result] == [
+        "sensor.humidity",
+        "sensor.temperature",
+    ]
+    temperature = result[1]
+    assert [point.value for point in temperature.points] == [21.0, 22.5]
+    assert temperature.points[0].timestamp == datetime(
+        2026, 6, 1, 12, 0, tzinfo=timezone.utc
+    )
+
+
+def test_normalize_history_payload_skips_non_numeric_and_non_finite_states() -> None:
+    payload = [
+        [
+            {
+                "entity_id": "sensor.temperature",
+                "state": state,
+                "last_changed": "2026-06-01T12:00:00+00:00",
+            }
+            for state in ("unknown", "unavailable", "nan", "inf", "-inf", True, None)
+        ]
+    ]
+
+    assert normalize_history_payload(payload) == []
+
+
+@pytest.mark.parametrize(
+    "payload",
+    [
+        {},
+        [{}],
+        [["invalid"]],
+        [[{"entity_id": "invalid", "state": "21", "last_changed": "2026-06-01"}]],
+        [[{"entity_id": "sensor.a", "state": "21", "last_changed": "invalid"}]],
+        [[{"state": "21", "last_changed": "2026-06-01T12:00:00+00:00"}]],
+        [
+            [
+                {
+                    "entity_id": "sensor.a",
+                    "state": "21",
+                    "last_changed": "2026-06-01T12:00:00+00:00",
+                },
+                {
+                    "entity_id": "sensor.b",
+                    "state": "22",
+                    "last_changed": "2026-06-01T12:01:00+00:00",
+                },
+            ]
+        ],
+    ],
+)
+def test_normalize_history_payload_rejects_malformed_structure(payload: object) -> None:
+    with pytest.raises(HaUnexpectedPayloadError):
+        normalize_history_payload(payload)
+
+
+def test_normalize_history_payload_accepts_empty_series() -> None:
+    assert normalize_history_payload([[]]) == []