Fix type hints.

For the model backend stub, we know that the type won't match, but we don't really care. We could make an abc that both the stub and the real class could inherit from, or we could subclass for the stub, but those seem overkill for this specific use case. It seems unlikely that type hints would show any real-life issues here.

test/test_log.py

@@ -16,6 +16,7 @@
 
 import io
 import logging
+import typing
 import unittest
 from unittest.mock import patch
 
@@ -26,15 +27,15 @@
 class FakeModelBackend:
 
     def __init__(self):
-        self._calls = []
+        self._calls : typing.List[typing.Tuple[str, str]] = []
 
-    def calls(self, clear=False):
+    def calls(self, clear: bool = False):
         calls = self._calls
         if clear:
             self._calls = []
         return calls
 
-    def juju_log(self, level, message):
+    def juju_log(self, level: str, message: str):
         for line in _ModelBackend.log_split(message):
             self._calls.append((level, line))
 
@@ -48,7 +49,7 @@ def tearDown(self):
         logging.getLogger().handlers.clear()
 
     def test_default_logging(self):
-        ops.log.setup_root_logging(self.backend)
+        ops.log.setup_root_logging(self.backend)  # type: ignore
 
         logger = logging.getLogger()
         self.assertEqual(logger.level, logging.DEBUG)
@@ -71,7 +72,7 @@ def test_default_logging(self):
     def test_handler_filtering(self):
         logger = logging.getLogger()
         logger.setLevel(logging.INFO)
-        logger.addHandler(ops.log.JujuLogHandler(self.backend, logging.WARNING))
+        logger.addHandler(ops.log.JujuLogHandler(self.backend, logging.WARNING))  # type: ignore
         logger.info('foo')
         self.assertEqual(self.backend.calls(), [])
         logger.warning('bar')
@@ -80,7 +81,7 @@ def test_handler_filtering(self):
     def test_no_stderr_without_debug(self):
         buffer = io.StringIO()
         with patch('sys.stderr', buffer):
-            ops.log.setup_root_logging(self.backend, debug=False)
+            ops.log.setup_root_logging(self.backend, debug=False)  # type: ignore
             logger = logging.getLogger()
             logger.debug('debug message')
             logger.info('info message')
@@ -98,7 +99,7 @@ def test_no_stderr_without_debug(self):
     def test_debug_logging(self):
         buffer = io.StringIO()
         with patch('sys.stderr', buffer):
-            ops.log.setup_root_logging(self.backend, debug=True)
+            ops.log.setup_root_logging(self.backend, debug=True)  # type: ignore
             logger = logging.getLogger()
             logger.debug('debug message')
             logger.info('info message')
@@ -120,7 +121,7 @@ def test_debug_logging(self):
         )
 
     def test_reduced_logging(self):
-        ops.log.setup_root_logging(self.backend)
+        ops.log.setup_root_logging(self.backend)  # type: ignore
         logger = logging.getLogger()
         logger.setLevel(logging.WARNING)
         logger.debug('debug')
@@ -132,7 +133,7 @@ def test_long_string_logging(self):
         buffer = io.StringIO()
 
         with patch('sys.stderr', buffer):
-            ops.log.setup_root_logging(self.backend, debug=True)
+            ops.log.setup_root_logging(self.backend, debug=True)  # type: ignore
             logger = logging.getLogger()
             logger.debug('l' * MAX_LOG_LINE_LEN)