Replace backoff with tenacity and handle always-off zones

Author: lexbrugman

poetry.lock

@@ -5,7 +5,7 @@ package-mode = false
 python = ">=3.13.2,<4.0"
 evohome-async = ">=1.0,<2"
 aiohttp = "^3.11"
-backoff = "^2.2"
+tenacity = "^9.1"
 
 [tool.poetry.group.dev.dependencies]
 pytest = "^9.0"

pyproject.toml

@@ -1,17 +1,22 @@
 import asyncio
-import backoff
 import logging
 import settings
 
 from datetime import datetime, timedelta
 from evohomeasync2 import EvohomeClientOld as EvohomeClient, ControlSystem, Location, Zone
 from evohomeasync2.schemas import SystemMode, ZoneMode
 from evohome_helper import weather
+from tenacity import retry, retry_if_exception_type, stop_after_attempt, wait_exponential
 from typing import Generator
 
 logger = logging.getLogger(__name__)
 _evohome_client = None
-_retry = backoff.on_exception(wait_gen=backoff.expo, exception=Exception, max_tries=6)
+_retry = retry(
+    retry=retry_if_exception_type(Exception),
+    wait=wait_exponential(),
+    stop=stop_after_attempt(6),
+    reraise=True,
+)
 
 _AWAY_MODE_MAP = {
     "auto": SystemMode.AUTO,
@@ -102,13 +107,17 @@ def _get_zone_switch_points(zone: Zone, now: datetime) -> list[tuple[datetime, f
     return result
 
 
-def _get_last_heating_switchpoint(zone: Zone, now: datetime) -> tuple[datetime, float]:
-    last_heating_datetime = now - timedelta(weeks=52)
-    last_heating_temperature = -99.0
+def _get_last_heating_switchpoint(zone: Zone, now: datetime) -> tuple[datetime, float] | None:
+    last_heating_datetime = None
+    last_heating_temperature = None
     for switchpoint_datetime, switchpoint_temperature in _get_zone_switch_points(zone, now):
         if not _is_considered_off(switchpoint_temperature):
             last_heating_datetime = switchpoint_datetime
             last_heating_temperature = switchpoint_temperature
+
+    if last_heating_datetime is None or last_heating_temperature is None:
+        return None
+
     return last_heating_datetime, last_heating_temperature
 
 
@@ -124,7 +133,12 @@ def is_in_schedule_grace_period(location: Location) -> bool:
 
     zones = get_zones(location)
     for zone in zones:
-        switch_point_start, switch_point_temperature = _get_last_heating_switchpoint(zone, now)
+        switch_point = _get_last_heating_switchpoint(zone, now)
+        if switch_point is None:
+            logger.debug("no scheduled heating switch point found for %s", zone.name)
+            continue
+
+        switch_point_start, switch_point_temperature = switch_point
         logger.debug(
             "last scheduled switch point for %s was at: %s (%s degrees celsius)",
             zone.name,

src/evohome_helper/evohome.py

@@ -162,6 +162,14 @@ def test_current_zone_switch_point_ignores_off_period(evohome_factory):
     assert sp_start == datetime(2024, 4, 7, 11, 55, 0)
 
 
+def test_get_last_heating_switchpoint_returns_none_when_zone_always_off(monkeypatch, evohome_factory):
+    state = evohome_factory.complete_state(schedule=evohome_factory.uniform_schedule(15, "11:55:00"))
+    monkeypatch.setattr("settings.EVOHOME_OFF_TEMP_THRESHOLD", 15)
+
+    now = datetime(2024, 4, 7, 12, 10, 0)
+    assert evohome._get_last_heating_switchpoint(state.zone, now) is None
+
+
 def test_is_in_schedule_grace_period_triggered_after_off_within_grace(monkeypatch, evohome_factory):
     """Grace period uses last heating start even if current period is off."""
     sp_heat = evohome_factory.switchpoint("11:55:00", 20)
@@ -176,6 +184,15 @@ def test_is_in_schedule_grace_period_triggered_after_off_within_grace(monkeypatc
         assert evohome.is_in_schedule_grace_period(state.location) is True
 
 
+def test_is_in_schedule_grace_period_false_when_zone_always_off(monkeypatch, evohome_factory):
+    state = evohome_factory.complete_state(schedule=evohome_factory.uniform_schedule(15, "11:55:00"))
+    monkeypatch.setattr("settings.PRESENCE_HEATING_SCHEDULE_GRACE_TIME", 900)
+    monkeypatch.setattr("settings.EVOHOME_OFF_TEMP_THRESHOLD", 15)
+
+    with freeze_time("2024-04-07 12:00:00"):
+        assert evohome.is_in_schedule_grace_period(state.location) is False
+
+
 def test_get_zones_filters_faulty_zones(evohome_factory):
     state = evohome_factory.complete_state(with_fault=False)
     faulty = evohome_factory.zone(name="bad", active_faults=["fault"])