From e482f8cd8504b36dc1ce2c1e51e0dee479d33249 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Wed, 2 May 2018 09:12:26 +0100
Subject: [PATCH] Fix incorrect reference to StringIO

This was introduced in 4f2f5171
---
 synapse/util/logformatter.py    |  2 +-
 tests/util/test_logformatter.py | 38 +++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 tests/util/test_logformatter.py

diff --git a/synapse/util/logformatter.py b/synapse/util/logformatter.py
index 59ab3c696..3e42868ea 100644
--- a/synapse/util/logformatter.py
+++ b/synapse/util/logformatter.py
@@ -32,7 +32,7 @@ class LogFormatter(logging.Formatter):
         super(LogFormatter, self).__init__(*args, **kwargs)
 
     def formatException(self, ei):
-        sio = StringIO.StringIO()
+        sio = StringIO()
         (typ, val, tb) = ei
 
         # log the stack above the exception capture point if possible, but
diff --git a/tests/util/test_logformatter.py b/tests/util/test_logformatter.py
new file mode 100644
index 000000000..1a1a8412f
--- /dev/null
+++ b/tests/util/test_logformatter.py
@@ -0,0 +1,38 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 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 sys
+
+from synapse.util.logformatter import LogFormatter
+from tests import unittest
+
+
+class TestException(Exception):
+    pass
+
+
+class LogFormatterTestCase(unittest.TestCase):
+    def test_formatter(self):
+        formatter = LogFormatter()
+
+        try:
+            raise TestException("testytest")
+        except TestException:
+            ei = sys.exc_info()
+
+        output = formatter.formatException(ei)
+
+        # check the output looks vaguely sane
+        self.assertIn("testytest", output)
+        self.assertIn("Capture point", output)