log.utils: Add Qt warning filter context manager.

qutebrowser/test/utils/test_log.py

@@ -29,6 +29,8 @@ from unittest import mock
 
 from qutebrowser.utils import log
 
+from PyQt5.QtCore import qWarning
+
 
 class BaseTest(unittest.TestCase):
 
@@ -219,5 +221,32 @@ class InitLogTests(BaseTest):
         log.init_log(self.args)
         sys.stderr = old_stderr
 
+
+class HideQtWarningTests(BaseTest):
+
+    """Tests for hide_qt_warning/QtWarningFilter."""
+
+    def test_unfiltered(self):
+        """Test a message which is not filtered."""
+        with log.hide_qt_warning("World", logger='qt-tests'):
+            with self.assertLogs('qt-tests', logging.WARNING):
+                qWarning("Hello World")
+
+    def test_filtered_exact(self):
+        """Test a message which is filtered (exact match)."""
+        with log.hide_qt_warning("Hello", logger='qt-tests'):
+            qWarning("Hello")
+
+    def test_filtered_start(self):
+        """Test a message which is filtered (match at line start)."""
+        with log.hide_qt_warning("Hello", logger='qt-tests'):
+            qWarning("Hello World")
+
+    def test_filtered_whitespace(self):
+        """Test a message which is filtered (match with whitespace)."""
+        with log.hide_qt_warning("Hello", logger='qt-tests'):
+            qWarning("  Hello World  ")
+
+
 if __name__ == '__main__':
     unittest.main()

qutebrowser/utils/log.py

@@ -308,6 +308,36 @@ def qt_message_handler(msg_type, context, msg):
     qt.handle(record)
 
 
+@contextlib.contextmanager
+def hide_qt_warning(pattern, logger='qt'):
+    """Hide Qt warnings matching the given regex."""
+    log_filter = QtWarningFilter(pattern)
+    logger_obj = logging.getLogger(logger)
+    logger_obj.addFilter(log_filter)
+    yield
+    logger_obj.removeFilter(log_filter)
+
+
+class QtWarningFilter(logging.Filter):
+
+    """Filter to filter Qt warnings.
+
+    Attributes:
+        _pattern: The start of the message.
+    """
+
+    def __init__(self, pattern):
+        super().__init__()
+        self._pattern = pattern
+
+    def filter(self, record):
+        """Determine if the specified record is to be logged."""
+        if record.msg.strip().startswith(self._pattern):
+            return False  # filter
+        else:
+            return True  # log
+
+
 class LogFilter(logging.Filter):
 
     """Filter to filter log records based on the commandline argument.