Mark ESPHome update entity unavailable when device is offline (#87576)

tests/components/esphome/test_update.py

@@ -145,3 +145,54 @@ async def test_update_static_info(
 
     state = hass.states.get("update.none_firmware")
     assert state.state == "off"
+
+
+async def test_update_device_state_for_availability(
+    hass,
+    mock_config_entry,
+    mock_device_info,
+    mock_dashboard,
+):
+    """Test ESPHome update entity changes availability with the device."""
+    mock_dashboard["configured"] = [
+        {
+            "name": "test",
+            "current_version": "1.2.3",
+        },
+    ]
+    await async_get_dashboard(hass).async_refresh()
+
+    signal_device_updated = f"esphome_{mock_config_entry.entry_id}_on_device_update"
+    runtime_data = Mock(
+        available=True,
+        device_info=mock_device_info,
+        signal_device_updated=signal_device_updated,
+    )
+
+    with patch(
+        "homeassistant.components.esphome.update.DomainData.get_entry_data",
+        return_value=runtime_data,
+    ):
+        assert await hass.config_entries.async_forward_entry_setup(
+            mock_config_entry, "update"
+        )
+
+    state = hass.states.get("update.none_firmware")
+    assert state is not None
+    assert state.state == "on"
+
+    runtime_data.available = False
+    async_dispatcher_send(hass, signal_device_updated)
+
+    state = hass.states.get("update.none_firmware")
+    assert state.state == "unavailable"
+
+    # Deep sleep devices should still be available
+    runtime_data.device_info = dataclasses.replace(
+        runtime_data.device_info, has_deep_sleep=True
+    )
+
+    async_dispatcher_send(hass, signal_device_updated)
+
+    state = hass.states.get("update.none_firmware")
+    assert state.state == "on"