diff --git a/tests/components/iometer/test_init.py b/tests/components/iometer/test_init.py
index 9d8eadc5079..68f75384d40 100644
--- a/tests/components/iometer/test_init.py
+++ b/tests/components/iometer/test_init.py
@@ -1,13 +1,17 @@
-"""Tests for the AirGradient integration."""
+"""Tests for the IOmeter integration."""
 
 from datetime import timedelta
 from unittest.mock import AsyncMock
 
 from freezegun.api import FrozenDateTimeFactory
+from iometer import IOmeterConnectionError
+import pytest
 
+from homeassistant.components.iometer import async_setup_entry
 from homeassistant.components.iometer.const import DOMAIN
 from homeassistant.const import Platform
 from homeassistant.core import HomeAssistant
+from homeassistant.exceptions import ConfigEntryNotReady
 from homeassistant.helpers import device_registry as dr
 
 from . import setup_platform
@@ -23,7 +27,8 @@ async def test_new_firmware_version(
     freezer: FrozenDateTimeFactory,
 ) -> None:
     """Test device registry integration."""
-    # await setup_integration(hass, mock_config_entry)
+    assert mock_config_entry.unique_id is not None
+
     await setup_platform(hass, mock_config_entry, [Platform.SENSOR])
     device_entry = device_registry.async_get_device(
         identifiers={(DOMAIN, mock_config_entry.unique_id)}
@@ -42,3 +47,21 @@ async def test_new_firmware_version(
     )
     assert device_entry is not None
     assert device_entry.sw_version == "build-62/build-69"
+
+
+async def test_async_setup_entry_connection_error(
+    hass: HomeAssistant,
+    mock_iometer_client: AsyncMock,
+    mock_config_entry: MockConfigEntry,
+) -> None:
+    """Test async_setup_entry raises ConfigEntryNotReady on connection error."""
+
+    mock_config_entry.add_to_hass(hass)
+    mock_iometer_client.get_current_status.side_effect = IOmeterConnectionError(
+        "cannot connect"
+    )
+
+    with pytest.raises(ConfigEntryNotReady):
+        await async_setup_entry(hass, mock_config_entry)
+
+    assert mock_iometer_client.get_current_status.await_count == 1