Add json test results format support for SwarmingIsolatedScriptTest

scripts/slave/recipe_modules/swarming/tests/collect_gtest_task_test.py

 #!/usr/bin/env python
 # 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 cStringIO
 import json
 import logging
 import os
 import shutil
@@ skipping 323 matching lines @@
     merged['swarming_summary'] = {
       'shards': [{
         'outputs_ref': {
           'view_url': 'blah',
         },
       }],
     }
     self.assertEqual(GOOD_GTEST_JSON_MERGED, merged)
     self.assertEqual('', stdout)
 
+  def test_merged_json_result_ok(self):
+    self.stage({
+      'summary.json': {'shards': [{'dummy': 0}, {'dummy': 0}, {'dummy': 0}]},
+      '0/output.json': GOOD_JSON_TEST_RESULT_0,
+      '1/output.json': GOOD_JSON_TEST_RESULT_1,
+      '2/output.json': GOOD_JSON_TEST_RESULT_2,
+    })
+    merged, stdout = self.call()
+    merged['swarming_summary'] = {
+      'shards': [{
+        'outputs_ref': {
+          'view_url': 'blah',
+        },
+      }],
+    }
+    self.assertEqual(GOOD_JSON_TEST_RESULT_MERGED, merged)
+    self.assertEqual('', stdout)
+
+
   def test_missing_summary_json(self):
     # summary.json is missing, should return None and emit warning.
     merged, output = self.call()
     self.assertEqual(None, merged)
     self.assertIn('@@@STEP_WARNINGS@@@', output)
     self.assertIn('summary.json is missing or can not be read', output)
 
   def test_unfinished_shards(self):
     # Only one shard (#1) finished. Shard #0 did not.
     self.stage({
@@ skipping 27 matching lines @@
         '@@@STEP_TEXT@3 disabled@@@',
         stdout)
 
 
 if __name__ == '__main__':
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.ERROR)
   if '-v' in sys.argv:
     unittest.TestCase.maxDiff = None
   unittest.main()