Warn if start takes a long time. (#6975)

* Warn if start takes a long time.

* ps - cleanup

* Tweak message

* Add tests

* Tweak messagE

tests/test_core.py

@@ -5,6 +5,7 @@ import unittest
 from unittest.mock import patch, MagicMock, sentinel
 from datetime import datetime, timedelta
 
+import logging
 import pytz
 import pytest
 
@@ -867,3 +868,45 @@ def test_timer_out_of_sync(mock_monotonic, loop):
     assert slp_seconds == 1
     assert callback is fire_time_event
     assert abs(nxt - 12.3) < 0.001
+
+
+@asyncio.coroutine
+def test_hass_start_starts_the_timer(loop):
+    """Test when hass starts, it starts the timer."""
+    hass = ha.HomeAssistant(loop=loop)
+
+    try:
+        with patch('homeassistant.core._async_create_timer') as mock_timer:
+            yield from hass.async_start()
+
+        assert hass.state == ha.CoreState.running
+        assert not hass._track_task
+        assert len(mock_timer.mock_calls) == 1
+        assert mock_timer.mock_calls[0][1][0] is hass
+
+    finally:
+        yield from hass.async_stop()
+        assert hass.state == ha.CoreState.not_running
+
+
+@asyncio.coroutine
+def test_start_taking_too_long(loop, caplog):
+    """Test when async_start takes too long."""
+    hass = ha.HomeAssistant(loop=loop)
+    caplog.set_level(logging.WARNING)
+
+    try:
+        with patch('homeassistant.core.timeout',
+                   side_effect=asyncio.TimeoutError), \
+             patch('homeassistant.core._async_create_timer') as mock_timer:
+            yield from hass.async_start()
+
+        assert not hass._track_task
+        assert hass.state == ha.CoreState.running
+        assert len(mock_timer.mock_calls) == 1
+        assert mock_timer.mock_calls[0][1][0] is hass
+        assert 'Something is blocking Home Assistant' in caplog.text
+
+    finally:
+        yield from hass.async_stop()
+        assert hass.state == ha.CoreState.not_running