Add unittest for gtest_test_results.

tools/telemetry/telemetry/results/base_test_results_unittest.py

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+import unittest
+import sys
+
+
+class TestOutputStream(object):
+  def __init__(self):
+    self.output_data = []
+
+  def write(self, data):
+    assert isinstance(data, str)
+    self.output_data.append(data)
+
+class BaseTestResultsUnittest(unittest.TestCase):
+
+  def CreateException(self):

[tonyg, 2014/06/11 23:08:51]

I know you're just moving this. But while you're here, can you convert it to an
IntentionalException. 

https://code.google.com/p/chromium/codesearch#chromium/src/tools/telemetry/te...

That exception doesn't print stacks that confuse sheriffs in unittests results.

[nednguyen, 2014/06/11 23:30:36]

Done.

+    try:
+      raise Exception('Intentional exception')
+    except Exception:
+      return sys.exc_info()
+
+  def assertEquals(self, ex, res):
+    # This helps diagnose result mismatches.
+    if ex != res and isinstance(ex, list):
+      def CleanList(l):
+        res = []
+        for x in l:
+          x = x.split('\n')
+          res.extend(x)
+        return res
+      ex = CleanList(ex)
+      res = CleanList(res)
+      max_len = max(len(ex), len(res))
+      max_width = max([len(x) for x in ex + res])
+      max_width = max(10, max_width)
+      print 'Lists differ!'
+      print '%*s | %*s' % (max_width, 'expected', max_width, 'result')
+      for i in range(max_len):
+        if i < len(ex):
+          e = ex[i]
+        else:
+          e = ''
+        if i < len(res):
+          r = res[i]
+        else:
+          r = ''
+        if e != r:
+          sep = '*'
+        else:
+          sep = '|'
+        print '%*s %s %*s' % (max_width, e, sep, max_width, r)
+      print ''
+    if ex != res and isinstance(ex, str) and isinstance(res, str):
+      print 'Strings differ!'
+      print 'exepected:\n%s' % repr(ex)
+      print 'result:\n%s\n' % repr(res)
+    super(BaseTestResultsUnittest, self).assertEquals(ex, res)