diff --git a/homeassistant/components/wwlln/__init__.py b/homeassistant/components/wwlln/__init__.py
index 676bdfcc0c1..fe5061f6ed4 100644
--- a/homeassistant/components/wwlln/__init__.py
+++ b/homeassistant/components/wwlln/__init__.py
@@ -29,9 +29,6 @@ CONFIG_SCHEMA = vol.Schema({
 
 async def async_setup(hass, config):
     """Set up the WWLLN component."""
-    hass.data[DOMAIN] = {}
-    hass.data[DOMAIN][DATA_CLIENT] = {}
-
     if DOMAIN not in config:
         return True
 
@@ -66,6 +63,9 @@ async def async_setup(hass, config):
 
 async def async_setup_entry(hass, config_entry):
     """Set up the WWLLN as config entry."""
+    hass.data[DOMAIN] = {}
+    hass.data[DOMAIN][DATA_CLIENT] = {}
+
     websession = aiohttp_client.async_get_clientsession(hass)
 
     hass.data[DOMAIN][DATA_CLIENT][config_entry.entry_id] = Client(websession)
diff --git a/tests/components/wwlln/conftest.py b/tests/components/wwlln/conftest.py
new file mode 100644
index 00000000000..b6514a7e318
--- /dev/null
+++ b/tests/components/wwlln/conftest.py
@@ -0,0 +1,23 @@
+"""Define various utilities for WWLLN tests."""
+import pytest
+
+from homeassistant.components.wwlln import CONF_WINDOW, DOMAIN
+from homeassistant.const import (
+    CONF_LATITUDE, CONF_LONGITUDE, CONF_RADIUS, CONF_UNIT_SYSTEM)
+
+from tests.common import MockConfigEntry
+
+
+@pytest.fixture
+def config_entry():
+    """Create a mock WWLLN config entry."""
+    return MockConfigEntry(
+        domain=DOMAIN,
+        data={
+            CONF_LATITUDE: 39.128712,
+            CONF_LONGITUDE: -104.9812612,
+            CONF_RADIUS: 25,
+            CONF_UNIT_SYSTEM: 'metric',
+            CONF_WINDOW: 3600
+        },
+        title='39.128712, -104.9812612')
diff --git a/tests/components/wwlln/test_config_flow.py b/tests/components/wwlln/test_config_flow.py
index 349dc19dce4..34d46bbd7c6 100644
--- a/tests/components/wwlln/test_config_flow.py
+++ b/tests/components/wwlln/test_config_flow.py
@@ -1,15 +1,16 @@
 """Define tests for the WWLLN config flow."""
 from datetime import timedelta
 
+from asynctest import patch
+
 from homeassistant import data_entry_flow
-from homeassistant.components.wwlln import CONF_WINDOW, DOMAIN, config_flow
+from homeassistant.components.wwlln import (
+    CONF_WINDOW, DATA_CLIENT, DOMAIN, async_setup_entry, config_flow)
 from homeassistant.const import (
     CONF_LATITUDE, CONF_LONGITUDE, CONF_RADIUS, CONF_UNIT_SYSTEM)
 
-from tests.common import MockConfigEntry
 
-
-async def test_duplicate_error(hass):
+async def test_duplicate_error(hass, config_entry):
     """Test that errors are shown when duplicates are added."""
     conf = {
         CONF_LATITUDE: 39.128712,
@@ -17,7 +18,7 @@ async def test_duplicate_error(hass):
         CONF_RADIUS: 25,
     }
 
-    MockConfigEntry(domain=DOMAIN, data=conf).add_to_hass(hass)
+    config_entry.add_to_hass(hass)
     flow = config_flow.WWLLNFlowHandler()
     flow.hass = hass
 
@@ -108,3 +109,15 @@ async def test_custom_window(hass):
         CONF_UNIT_SYSTEM: 'metric',
         CONF_WINDOW: 3600,
     }
+
+
+async def test_component_load_config_entry(hass, config_entry):
+    """Test that loading an existing config entry yields a client."""
+    config_entry.add_to_hass(hass)
+    with patch.object(
+            hass.config_entries, 'async_forward_entry_setup') as forward_mock:
+        assert await async_setup_entry(hass, config_entry)
+
+        await hass.async_block_till_done()
+        assert forward_mock.call_count == 1
+        assert len(hass.data[DOMAIN][DATA_CLIENT]) == 1