From aafe6ff0e295e870a4a0b344a6880c97109d31b3 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Fri, 29 Apr 2022 01:48:58 -0500
Subject: [PATCH] Fix history_stats for timezones with a positive offset from
 UTC (#71038)

---
 .../components/history_stats/data.py          |  4 +-
 tests/components/history_stats/test_sensor.py | 81 +++++++++++++++++++
 2 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/homeassistant/components/history_stats/data.py b/homeassistant/components/history_stats/data.py
index c5d0ee0fb15..3f22f4cc32b 100644
--- a/homeassistant/components/history_stats/data.py
+++ b/homeassistant/components/history_stats/data.py
@@ -11,6 +11,8 @@ import homeassistant.util.dt as dt_util
 
 from .helpers import async_calculate_period, floored_timestamp
 
+MIN_TIME_UTC = datetime.datetime.min.replace(tzinfo=dt_util.UTC)
+
 
 @dataclass
 class HistoryStatsState:
@@ -36,7 +38,7 @@ class HistoryStats:
         """Init the history stats manager."""
         self.hass = hass
         self.entity_id = entity_id
-        self._period = (datetime.datetime.min, datetime.datetime.min)
+        self._period = (MIN_TIME_UTC, MIN_TIME_UTC)
         self._state: HistoryStatsState = HistoryStatsState(None, None, self._period)
         self._history_current_period: list[State] = []
         self._previous_run_before_start = False
diff --git a/tests/components/history_stats/test_sensor.py b/tests/components/history_stats/test_sensor.py
index 40a13116026..bfa0c8f415e 100644
--- a/tests/components/history_stats/test_sensor.py
+++ b/tests/components/history_stats/test_sensor.py
@@ -1306,3 +1306,84 @@ async def test_measure_from_end_going_backwards(hass, recorder_mock):
     assert hass.states.get("sensor.sensor2").state == "0.83"
     assert hass.states.get("sensor.sensor3").state == "1"
     assert hass.states.get("sensor.sensor4").state == "83.3"
+
+
+async def test_measure_cet(hass, recorder_mock):
+    """Test the history statistics sensor measure with a non-UTC timezone."""
+    hass.config.set_time_zone("Europe/Berlin")
+    start_time = dt_util.utcnow() - timedelta(minutes=60)
+    t0 = start_time + timedelta(minutes=20)
+    t1 = t0 + timedelta(minutes=10)
+    t2 = t1 + timedelta(minutes=10)
+
+    # Start     t0        t1        t2        End
+    # |--20min--|--20min--|--10min--|--10min--|
+    # |---off---|---on----|---off---|---on----|
+
+    def _fake_states(*args, **kwargs):
+        return {
+            "binary_sensor.test_id": [
+                ha.State("binary_sensor.test_id", "on", last_changed=t0),
+                ha.State("binary_sensor.test_id", "off", last_changed=t1),
+                ha.State("binary_sensor.test_id", "on", last_changed=t2),
+            ]
+        }
+
+    await async_setup_component(
+        hass,
+        "sensor",
+        {
+            "sensor": [
+                {
+                    "platform": "history_stats",
+                    "entity_id": "binary_sensor.test_id",
+                    "name": "sensor1",
+                    "state": "on",
+                    "start": "{{ as_timestamp(now()) - 3600 }}",
+                    "end": "{{ now() }}",
+                    "type": "time",
+                },
+                {
+                    "platform": "history_stats",
+                    "entity_id": "binary_sensor.test_id",
+                    "name": "sensor2",
+                    "state": "on",
+                    "start": "{{ as_timestamp(now()) - 3600 }}",
+                    "end": "{{ now() }}",
+                    "type": "time",
+                },
+                {
+                    "platform": "history_stats",
+                    "entity_id": "binary_sensor.test_id",
+                    "name": "sensor3",
+                    "state": "on",
+                    "start": "{{ as_timestamp(now()) - 3600 }}",
+                    "end": "{{ now() }}",
+                    "type": "count",
+                },
+                {
+                    "platform": "history_stats",
+                    "entity_id": "binary_sensor.test_id",
+                    "name": "sensor4",
+                    "state": "on",
+                    "start": "{{ as_timestamp(now()) - 3600 }}",
+                    "end": "{{ now() }}",
+                    "type": "ratio",
+                },
+            ]
+        },
+    )
+    await hass.async_block_till_done()
+
+    with patch(
+        "homeassistant.components.recorder.history.state_changes_during_period",
+        _fake_states,
+    ):
+        for i in range(1, 5):
+            await async_update_entity(hass, f"sensor.sensor{i}")
+        await hass.async_block_till_done()
+
+    assert hass.states.get("sensor.sensor1").state == "0.83"
+    assert hass.states.get("sensor.sensor2").state == "0.83"
+    assert hass.states.get("sensor.sensor3").state == "1"
+    assert hass.states.get("sensor.sensor4").state == "83.3"