diff --git a/tests/test_component_device_scanner.py b/tests/test_component_device_scanner.py
index 1accc1c5ff8..47ad6f7d798 100644
--- a/tests/test_component_device_scanner.py
+++ b/tests/test_component_device_scanner.py
@@ -117,9 +117,17 @@ class TestComponentsDeviceTracker(unittest.TestCase):
         dev3 = device_tracker.ENTITY_ID_FORMAT.format('DEV3')
 
         now = datetime.now()
-        nowAlmostMinGone = (now + device_tracker.TIME_DEVICE_NOT_FOUND -
-                            timedelta(seconds=1))
-        nowMinGone = nowAlmostMinGone + timedelta(seconds=2)
+
+        # Device scanner scans every 12 seconds. We need to sync our times to
+        # be every 12 seconds or else the time_changed event will be ignored.
+        nowAlmostMinimumGone = now + device_tracker.TIME_DEVICE_NOT_FOUND
+        nowAlmostMinimumGone -= timedelta(
+            seconds=(nowAlmostMinimumGone.second % 12))
+
+        nowMinimumGone = now + device_tracker.TIME_DEVICE_NOT_FOUND
+        nowMinimumGone += timedelta(seconds=12-(nowMinimumGone.second % 12))
+
+        print(now, nowAlmostMinimumGone, nowMinimumGone)
 
         # Test initial is correct
         self.assertTrue(device_tracker.is_on(self.hass))
@@ -168,7 +176,7 @@ class TestComponentsDeviceTracker(unittest.TestCase):
 
         # Test if device leaves what happens, test the time span
         self.hass.bus.fire(
-            ha.EVENT_TIME_CHANGED, {ha.ATTR_NOW: nowAlmostMinGone})
+            ha.EVENT_TIME_CHANGED, {ha.ATTR_NOW: nowAlmostMinimumGone})
 
         self.hass.pool.block_till_done()
 
@@ -179,7 +187,8 @@ class TestComponentsDeviceTracker(unittest.TestCase):
         self.assertTrue(device_tracker.is_on(self.hass, dev3))
 
         # Now test if gone for longer then error margin
-        self.hass.bus.fire(ha.EVENT_TIME_CHANGED, {ha.ATTR_NOW: nowMinGone})
+        self.hass.bus.fire(
+            ha.EVENT_TIME_CHANGED, {ha.ATTR_NOW: nowMinimumGone})
 
         self.hass.pool.block_till_done()