feat: add dvhubonline feed-in tariff provider (#1193)

Fetches GET /api/prices?start&end&zone (15-min slots, EUR/MWh) and stores
the raw market price as feed_in_tariff_wh (EUR/Wh) — no import charges/VAT.

Slots beyond the day-ahead horizon are left to the consumer's forward-fill
(FeedInTariffImport behaviour).

5 unit tests + opt-in live smoke (EOS_DVHUB_ONLINE_LIVE=1, passing).

Signed-off-by: Christin <info@bikinibottom.capital>
Signed-off-by: Bobby Noelte <b0661n0e17e@gmail.com>

tests/test_feedintariffdvhubonline.py

@@ -0,0 +1,71 @@
+"""Tests for the dvhub.online feed-in tariff provider."""
+
+import os
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from akkudoktoreos.prediction.feedintariffdvhubonline import (
+    FeedInTariffDvhubOnline,
+    FeedInTariffDvhubOnlineCommonSettings,
+)
+
+SAMPLE = {
+    "data": [
+        {"ts": "2026-07-19T12:00:00.000Z", "price": 42.5},   # EUR/MWh
+        {"ts": "2026-07-19T12:15:00.000Z", "price": -5.69},  # negative slot
+        {"ts": "bogus", "price": 10.0},                      # malformed -> skipped
+        {"ts": "2026-07-19T12:30:00.000Z", "price": "x"},    # malformed -> skipped
+    ]
+}
+
+
+@pytest.fixture
+def provider(config_eos):
+    config_eos.merge_settings_from_dict(
+        {"feedintariff": {"provider": "FeedInTariffDvhubOnline"}}
+    )
+    return FeedInTariffDvhubOnline()
+
+
+class TestFeedInTariffDvhubOnline:
+    def test_provider_id_registered(self, provider, config_eos):
+        assert provider.provider_id() == "FeedInTariffDvhubOnline"
+        assert provider.enabled()
+        assert "FeedInTariffDvhubOnline" in config_eos.feedintariff.providers
+
+    def test_parse_data_eur_mwh_to_eur_wh(self, provider):
+        series = provider._parse_data(SAMPLE)
+        assert len(series) == 2  # malformed entries skipped
+        assert series.iloc[0] == pytest.approx(42.5 / 1_000_000)
+        assert series.iloc[1] == pytest.approx(-5.69 / 1_000_000)  # negatives kept
+
+    def test_default_settings(self, provider):
+        settings = provider._provider_settings()
+        assert settings.base_url == "https://dvhub.online"
+        assert settings.zone == "DE-LU"
+
+    def test_request_shape_guard(self, provider):
+        response = MagicMock()
+        response.raise_for_status.return_value = None
+        response.json.return_value = {"unexpected": True}
+        with patch(
+            "akkudoktoreos.prediction.feedintariffdvhubonline.requests.get",
+            return_value=response,
+        ):
+            with pytest.raises(ValueError, match="response shape"):
+                provider._request_forecast(
+                    start_date="2026-07-19", end_date="2026-07-21", force_update=True
+                )
+
+
+@pytest.mark.skipif(
+    os.environ.get("EOS_DVHUB_ONLINE_LIVE") != "1",
+    reason="live API smoke — set EOS_DVHUB_ONLINE_LIVE=1 to run",
+)
+def test_live_api_smoke(provider):
+    data = provider._request_forecast(
+        start_date="2026-07-19", end_date="2026-07-20", force_update=True
+    )
+    series = provider._parse_data(data)
+    assert not series.empty