Makes sure telemetry test result report is one string (no interreuption)

tools/telemetry/telemetry/results/gtest_progress_reporter.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 time
 
 from telemetry.results import progress_reporter
 from telemetry.value import failure
 from telemetry.value import skip
 
 
 class GTestProgressReporter(progress_reporter.ProgressReporter):
-  """A progress reporter that outputs the progress report in gtest style."""
+  """A progress reporter that outputs the progress report in gtest style.
+
+  Be careful each print should only handle one string. Otherwise, the output
+  might be interrupted by Chrome logging, and the output interpretation might
+  be incorrect. For example:
+      print >> self._output_stream, "[ OK ]", testname
+  should be written as
+      print >> self._output_stream, "[ OK ] %s" % testname
+  """
 
   def __init__(self, output_stream, output_skipped_tests_summary=False):
     super(GTestProgressReporter, self).__init__()
     self._output_stream = output_stream
     self._timestamp = None
     self._output_skipped_tests_summary = output_skipped_tests_summary
 
   def _GetMs(self):
     assert self._timestamp is not None, 'Did not call WillRunPage.'
     return (time.time() - self._timestamp) * 1000
 
   def DidAddValue(self, value):
     super(GTestProgressReporter, self).DidAddValue(value)
     if isinstance(value, failure.FailureValue):
       print >> self._output_stream, failure.GetStringFromExcInfo(
           value.exc_info)
       self._output_stream.flush()
     elif isinstance(value, skip.SkipValue):
       print >> self._output_stream, '===== SKIPPING TEST %s: %s =====' % (
           value.page.display_name, value.reason)
     # TODO(chrishenry): Consider outputting metric values as well. For
     # e.g., it can replace BuildbotOutputFormatter in
     # --output-format=html, which we used only so that users can grep
     # the results without opening results.html.
 
   def WillRunPage(self, page_test_results):
     super(GTestProgressReporter, self).WillRunPage(page_test_results)
-    print >> self._output_stream, '[ RUN      ]', (
+    print >> self._output_stream, '[ RUN      ] %s' % (
         page_test_results.current_page.display_name)
     self._output_stream.flush()
     self._timestamp = time.time()
 
   def DidRunPage(self, page_test_results):
     super(GTestProgressReporter, self).DidRunPage(page_test_results)
     page = page_test_results.current_page
     if page_test_results.current_page_run.failed:
-      print >> self._output_stream, '[  FAILED  ]', page.display_name, (
-          '(%0.f ms)' % self._GetMs())
+      print >> self._output_stream, '[  FAILED  ] %s (%0.f ms)' % (
+          page.display_name, self._GetMs())
     else:
-      print >> self._output_stream, '[       OK ]', page.display_name, (
-          '(%0.f ms)' % self._GetMs())
+      print >> self._output_stream, '[       OK ] %s (%0.f ms)' % (
+          page.display_name, self._GetMs())
     self._output_stream.flush()
 
   def WillAttemptPageRun(self, page_test_results, attempt_count, max_attempts):
     super(GTestProgressReporter, self).WillAttemptPageRun(
         page_test_results, attempt_count, max_attempts)
     # A failed attempt will have at least 1 value.
     if attempt_count != 1:
       print >> self._output_stream, (
           '===== RETRYING PAGE RUN (attempt %s out of %s allowed) =====' % (
               attempt_count, max_attempts))
       print >> self._output_stream, (
           'Page run attempt failed and will be retried. '
           'Discarding previous results.')
 
   def DidFinishAllTests(self, page_test_results):
     super(GTestProgressReporter, self).DidFinishAllTests(page_test_results)
     successful_runs = []
     failed_runs = []
     for run in page_test_results.all_page_runs:
       if run.failed:
         failed_runs.append(run)
       else:
         successful_runs.append(run)
 
     unit = 'test' if len(successful_runs) == 1 else 'tests'
-    print >> self._output_stream, '[  PASSED  ]', (
-        '%d %s.' % (len(successful_runs), unit))
+    print >> self._output_stream, '[  PASSED  ] %d %s.' % (
+        (len(successful_runs), unit))
     if len(failed_runs) > 0:
       unit = 'test' if len(failed_runs) == 1 else 'tests'
-      print >> self._output_stream, '[  FAILED  ]', (
-          '%d %s, listed below:' % (len(page_test_results.failures), unit))
+      print >> self._output_stream, '[  FAILED  ] %d %s, listed below:' % (
+          (len(page_test_results.failures), unit))
       for failed_run in failed_runs:
-        print >> self._output_stream, '[  FAILED  ] ', (
+        print >> self._output_stream, '[  FAILED  ]  %s' % (
             failed_run.page.display_name)
       print >> self._output_stream
       count = len(failed_runs)
       unit = 'TEST' if count == 1 else 'TESTS'
       print >> self._output_stream, '%d FAILED %s' % (count, unit)
     print >> self._output_stream
 
     if self._output_skipped_tests_summary:
       if len(page_test_results.skipped_values) > 0:
         print >> self._output_stream, 'Skipped pages:\n%s\n' % ('\n'.join(
             v.page.display_name for v in page_test_results.skipped_values))
 
     self._output_stream.flush()