Added more details to failures of memory_test on the GPU bots.

content/test/gpu/gpu_tests/memory.py

 # Copyright (c) 2012 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 memory_expectations
 
 from telemetry import test
 from telemetry.page import page_test
 from telemetry.core.timeline import counter
 from telemetry.core.timeline import model
 
@@ skipping 45 matching lines @@
 class _MemoryValidator(page_test.PageTest):
   def ValidatePage(self, page, tab, results):
     timeline_data = tab.browser.StopTracing()
     timeline_model = model.TimelineModel(timeline_data)
     for process in timeline_model.GetAllProcesses():
       if 'gpu.GpuMemoryUsage' in process.counters:
         counter = process.GetCounter('gpu', 'GpuMemoryUsage')
         mb_used = counter.samples[-1] / 1048576
 
     if mb_used + WIGGLE_ROOM_MB < SINGLE_TAB_LIMIT_MB:
-      raise page_test.Failure('Memory allocation too low')
+      raise page_test.Failure(self._FormatException('low', mb_used))
 
     if mb_used - WIGGLE_ROOM_MB > MEMORY_LIMIT_MB:
-      raise page_test.Failure('Memory allocation too high')
+      raise page_test.Failure(self._FormatException('high', mb_used))
 
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArgs('--enable-logging')
     options.AppendExtraBrowserArgs(
         '--force-gpu-mem-available-mb=%s' % MEMORY_LIMIT_MB)
 
   def WillNavigateToPage(self, page, tab):
     custom_categories = ['webkit.console', 'gpu']
     tab.browser.StartTracing(','.join(custom_categories), 60)
 
+  def _FormatException(self, low_or_high, mb_used):
+    return 'Memory allocation too %s (was %d MB, should be %d MB +/- %d MB)' % (
+      low_or_high, mb_used, SINGLE_TAB_LIMIT_MB, WIGGLE_ROOM_MB)
+
 class Memory(test.Test):
   """Tests GPU memory limits"""
   test = _MemoryValidator
   page_set = 'page_sets/memory_tests.py'
 
   def CreateExpectations(self, page_set):
     return memory_expectations.MemoryExpectations()
 
   def CreatePageSet(self, options):
     page_set = super(Memory, self).CreatePageSet(options)
     for page in page_set.pages:
       page.script_to_evaluate_on_commit = test_harness_script
     return page_set