Unit tests to improve core coverage (#9659)

* Code coverage of logging util

* Improve async util coverage

* Add test coverage for restore_state

* get_random_string test

tests/util/test_logging.py

@@ -0,0 +1,68 @@
+"""Test Home Assistant logging util methods."""
+import asyncio
+import logging
+import threading
+
+import homeassistant.util.logging as logging_util
+
+
+@asyncio.coroutine
+def test_sensitive_data_filter():
+    """Test the logging sensitive data filter."""
+    log_filter = logging_util.HideSensitiveDataFilter('mock_sensitive')
+
+    clean_record = logging.makeLogRecord({'msg': "clean log data"})
+    log_filter.filter(clean_record)
+    assert clean_record.msg == "clean log data"
+
+    sensitive_record = logging.makeLogRecord({'msg': "mock_sensitive log"})
+    log_filter.filter(sensitive_record)
+    assert sensitive_record.msg == "******* log"
+
+
+@asyncio.coroutine
+def test_async_handler_loop_log(loop):
+    """Test the logging sensitive data filter."""
+    loop._thread_ident = threading.get_ident()
+
+    queue = asyncio.Queue(loop=loop)
+    base_handler = logging.handlers.QueueHandler(queue)
+    handler = logging_util.AsyncHandler(loop, base_handler)
+
+    # Test passthrough props and noop functions
+    assert handler.createLock() is None
+    assert handler.acquire() is None
+    assert handler.release() is None
+    assert handler.formatter is base_handler.formatter
+    assert handler.name is base_handler.get_name()
+    handler.name = 'mock_name'
+    assert base_handler.get_name() == 'mock_name'
+
+    log_record = logging.makeLogRecord({'msg': "Test Log Record"})
+    handler.emit(log_record)
+    yield from handler.async_close(True)
+    assert queue.get_nowait() == log_record
+    assert queue.empty()
+
+
+@asyncio.coroutine
+def test_async_handler_thread_log(loop):
+    """Test the logging sensitive data filter."""
+    loop._thread_ident = threading.get_ident()
+
+    queue = asyncio.Queue(loop=loop)
+    base_handler = logging.handlers.QueueHandler(queue)
+    handler = logging_util.AsyncHandler(loop, base_handler)
+
+    log_record = logging.makeLogRecord({'msg': "Test Log Record"})
+
+    def add_log():
+        """Emit a mock log."""
+        handler.emit(log_record)
+        handler.close()
+
+    yield from loop.run_in_executor(None, add_log)
+    yield from handler.async_close(True)
+
+    assert queue.get_nowait() == log_record
+    assert queue.empty()