Log exceptions that terminate CQ loop

tests/commit_queue_test.py

Index: tests/commit_queue_test.py
diff --git a/tests/commit_queue_test.py b/tests/commit_queue_test.py
index 049c29b5f34e565120461e7550e8c19f9a62f60d..d9c5ecc33d744a76e1689f3dd67cd2b25214032f 100755
--- a/tests/commit_queue_test.py
+++ b/tests/commit_queue_test.py
@@ -5,10 +5,12 @@
 
 """Unit tests for commit_queue.py."""
 
+import logging
 import os
 import StringIO
 import sys
 import time
+import traceback
 import unittest
 
 ROOT_DIR = os.path.dirname(os.path.abspath(__file__))
@@ -73,6 +75,14 @@ class CommitQueueTest(auto_stub.TestCase):
     self.mock(sys, 'stdout', StringIO.StringIO())
     self.mock(sys, 'stderr', StringIO.StringIO())
     self.mock(commit_queue.projects, 'load_project', None)
+    self.mock(commit_queue, 'SetupLogging', lambda _: None)
+    # Setup logging attached to the mocked sys.stderr, printing
+    # only the exception name to make tests less fragile.
+    handler = logging.StreamHandler()
+    formatter = logging.Formatter()
+    formatter.formatException = lambda _: traceback.format_exc(0)
+    handler.setFormatter(formatter)
+    logging.getLogger().handlers = [handler]
     self._time = 1
     self.mock(time, 'time', self._get_time)
     self.mock(creds, 'Credentials', self._get_cred)
@@ -142,7 +152,12 @@ class CommitQueueTest(auto_stub.TestCase):
         'Using read-only Rietveld\n'
         'Using read-only checkout\n'
         'Using read-only chromium-status interface\n')
-    self._check('stderr', 'Saving db...     \nDone!            \n')
+    self._check(
+        'stderr',
+        'CQ loop terminating\n'
+        'Traceback (most recent call last):\n'
+        'Stop\n\n'
+        'Saving db...\ndb save successful.\n')
 
   def testDryRun(self):
     sys.argv.extend(('--project', 'chromium'))
@@ -166,7 +181,12 @@ class CommitQueueTest(auto_stub.TestCase):
         'Using read-only Rietveld\n'
         'Using read-only checkout\n'
         'Using read-only chromium-status interface\n')
-    self._check('stderr', 'Saving db...     \nDone!            \n')
+    self._check(
+        'stderr',
+        'CQ loop terminating\n'
+        'Traceback (most recent call last):\n'
+        'Stop\n\n'
+        'Saving db...\ndb save successful.\n')
 
 
 if __name__ == '__main__':