Properly handle SVN connection/client errors.

This requires my fork of the SVN library, until pull request #43 is merged
upstream: https://github.com/dsoprea/PySvn/pull/43

tests/test_subversion.py

@@ -9,6 +9,7 @@ import unittest
 
 from dateutil.tz import tzutc
 import mock
+import svn.common
 
 import logging_config
 from attract_server import subversion
@@ -122,3 +123,18 @@ class TestCommitLogObserver(unittest.TestCase):
                          blinks[1])
         self.assertEqual({'log_entry': SVN_LOG_BATCH_WITH_TASK_MARKERS[2], 'task_id': 'T4433'},
                          blinks[2])
+
+    def test_svn_error(self):
+        """SVN errors should not crash the observer."""
+
+        self.mock_client.log_default = mock.Mock(name='log_default',
+                                                 side_effect=svn.common.SvnCommandError('unittest'))
+
+        record_blink = mock.Mock(name='record_blink',
+                                 spec={'__name__': 'record_blink'})
+        subversion.task_logged.connect(record_blink)
+
+        self.observer.fetch_and_observe()
+
+        record_blink.assert_not_called()
+        self.mock_client.log_default.assert_called_once()