Enforce a minimum temperature range for nest thermostats (#98238)

homeassistant/components/nest/climate.py

@@ -75,6 +75,7 @@ FAN_INV_MODES = list(FAN_INV_MODE_MAP)
 MAX_FAN_DURATION = 43200  # 15 hours is the max in the SDM API
 MIN_TEMP = 10
 MAX_TEMP = 32
+MIN_TEMP_RANGE = 1.66667
 
 
 async def async_setup_entry(
@@ -313,6 +314,13 @@ class ThermostatEntity(ClimateEntity):
         try:
             if self.preset_mode == PRESET_ECO or hvac_mode == HVACMode.HEAT_COOL:
                 if low_temp and high_temp:
+                    if high_temp - low_temp < MIN_TEMP_RANGE:
+                        # Ensure there is a minimum gap from the new temp. Pick
+                        # the temp that is not changing as the one to move.
+                        if abs(high_temp - self.target_temperature_high) < 0.01:
+                            high_temp = low_temp + MIN_TEMP_RANGE
+                        else:
+                            low_temp = high_temp - MIN_TEMP_RANGE
                     await trait.set_range(low_temp, high_temp)
             elif hvac_mode == HVACMode.COOL and temp:
                 await trait.set_cool(temp)

tests/components/nest/test_climate.py

@@ -758,6 +758,75 @@ async def test_thermostat_set_temperature_hvac_mode(
     }
 
 
+@pytest.mark.parametrize(
+    ("setpoint", "target_low", "target_high", "expected_params"),
+    [
+        (
+            {
+                "heatCelsius": 19.0,
+                "coolCelsius": 25.0,
+            },
+            19.0,
+            20.0,
+            # Cool is accepted and lowers heat by the min range
+            {"heatCelsius": 18.33333, "coolCelsius": 20.0},
+        ),
+        (
+            {
+                "heatCelsius": 19.0,
+                "coolCelsius": 25.0,
+            },
+            24.0,
+            25.0,
+            # Cool is accepted and lowers heat by the min range
+            {"heatCelsius": 24.0, "coolCelsius": 25.66667},
+        ),
+    ],
+)
+async def test_thermostat_set_temperature_range_too_close(
+    hass: HomeAssistant,
+    setup_platform: PlatformSetup,
+    auth: FakeAuth,
+    create_device: CreateDevice,
+    setpoint: dict[str, Any],
+    target_low: float,
+    target_high: float,
+    expected_params: dict[str, Any],
+) -> None:
+    """Test setting an HVAC temperature range that is too small of a range."""
+    create_device.create(
+        {
+            "sdm.devices.traits.ThermostatHvac": {"status": "OFF"},
+            "sdm.devices.traits.ThermostatMode": {
+                "availableModes": ["HEAT", "COOL", "HEATCOOL", "OFF"],
+                "mode": "HEATCOOL",
+            },
+            "sdm.devices.traits.ThermostatTemperatureSetpoint": setpoint,
+        },
+    )
+    await setup_platform()
+
+    assert len(hass.states.async_all()) == 1
+    thermostat = hass.states.get("climate.my_thermostat")
+    assert thermostat is not None
+    assert thermostat.state == HVACMode.HEAT_COOL
+
+    # Move the target temp to be in too small of a range
+    await common.async_set_temperature(
+        hass,
+        target_temp_low=target_low,
+        target_temp_high=target_high,
+    )
+    await hass.async_block_till_done()
+
+    assert auth.method == "post"
+    assert auth.url == DEVICE_COMMAND
+    assert auth.json == {
+        "command": "sdm.devices.commands.ThermostatTemperatureSetpoint.SetRange",
+        "params": expected_params,
+    }
+
+
 async def test_thermostat_set_heat_cool(
     hass: HomeAssistant,
     setup_platform: PlatformSetup,