Enable configuring test log level via env var (#4506)

I got fed up with always adding '@unittest.DEBUG' every time I needed to debug a test.

changelog.d/4506.misc

@@ -0,0 +1 @@
+Make it possible to set the log level for tests via an environment variable

tests/test_utils/__init__.py

@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Utilities for running the unit tests
+"""

tests/test_utils/logging_setup.py

@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+import os
+
+import twisted.logger
+
+from synapse.util.logcontext import LoggingContextFilter
+
+
+class ToTwistedHandler(logging.Handler):
+    """logging handler which sends the logs to the twisted log"""
+    tx_log = twisted.logger.Logger()
+
+    def emit(self, record):
+        log_entry = self.format(record)
+        log_level = record.levelname.lower().replace('warning', 'warn')
+        self.tx_log.emit(
+            twisted.logger.LogLevel.levelWithName(log_level),
+            log_entry.replace("{", r"(").replace("}", r")"),
+        )
+
+
+def setup_logging():
+    """Configure the python logging appropriately for the tests.
+
+    (Logs will end up in _trial_temp.)
+    """
+    root_logger = logging.getLogger()
+
+    log_format = (
+        "%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s"
+    )
+
+    handler = ToTwistedHandler()
+    formatter = logging.Formatter(log_format)
+    handler.setFormatter(formatter)
+    handler.addFilter(LoggingContextFilter(request=""))
+    root_logger.addHandler(handler)
+
+    log_level = os.environ.get("SYNAPSE_TEST_LOG_LEVEL", "ERROR")
+    root_logger.setLevel(log_level)

tests/unittest.py

@@ -31,38 +31,14 @@ from synapse.http.server import JsonResource
 from synapse.http.site import SynapseRequest
 from synapse.server import HomeServer
 from synapse.types import UserID, create_requester
-from synapse.util.logcontext import LoggingContext, LoggingContextFilter
+from synapse.util.logcontext import LoggingContext
 
 from tests.server import get_clock, make_request, render, setup_test_homeserver
+from tests.test_utils.logging_setup import setup_logging
 from tests.utils import default_config, setupdb
 
 setupdb()
-
-# Set up putting Synapse's logs into Trial's.
-rootLogger = logging.getLogger()
-
-log_format = (
-    "%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s"
-)
-
-
-class ToTwistedHandler(logging.Handler):
-    tx_log = twisted.logger.Logger()
-
-    def emit(self, record):
-        log_entry = self.format(record)
-        log_level = record.levelname.lower().replace('warning', 'warn')
-        self.tx_log.emit(
-            twisted.logger.LogLevel.levelWithName(log_level),
-            log_entry.replace("{", r"(").replace("}", r")"),
-        )
-
-
-handler = ToTwistedHandler()
-formatter = logging.Formatter(log_format)
-handler.setFormatter(formatter)
-handler.addFilter(LoggingContextFilter(request=""))
-rootLogger.addHandler(handler)
+setup_logging()
 
 
 def around(target):
@@ -96,7 +72,7 @@ class TestCase(unittest.TestCase):
 
         method = getattr(self, methodName)
 
-        level = getattr(method, "loglevel", getattr(self, "loglevel", logging.WARNING))
+        level = getattr(method, "loglevel", getattr(self, "loglevel", None))
 
         @around(self)
         def setUp(orig):
@@ -114,7 +90,7 @@ class TestCase(unittest.TestCase):
                 )
 
             old_level = logging.getLogger().level
-            if old_level != level:
+            if level is not None and old_level != level:
 
                 @around(self)
                 def tearDown(orig):
@@ -123,6 +99,7 @@ class TestCase(unittest.TestCase):
                     return ret
 
                 logging.getLogger().setLevel(level)
+
             return orig()
 
         @around(self)