Add json test results format support for SwarmingIsolatedScriptTest

scripts/slave/recipe_modules/swarming/results_merger.py

Index: scripts/slave/recipe_modules/swarming/results_merger.py
diff --git a/scripts/slave/recipe_modules/swarming/results_merger.py b/scripts/slave/recipe_modules/swarming/results_merger.py
new file mode 100644
index 0000000000000000000000000000000000000000..0fb21ae421990e019e4285a4ceab923ac8e5e44e
--- /dev/null
+++ b/scripts/slave/recipe_modules/swarming/results_merger.py
@@ -0,0 +1,111 @@
+# Copyright 2016 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 copy
+
+
+def merge_test_results(shard_results_list):
+  """ Merge list of results.
+
+  Args:
+    shard_results_list: list of results to merge. All the results must have the
+      same format. Supported format are simplified JSON format & Chromium JSON
+      test results format version 3 (see
+      https://www.chromium.org/developers/the-json-test-results-format)
+
+  Returns:
+    a dictionary that represent the merged results. Its format follow the same
+    format of all results in |shard_results_list|.
+  """
+  if 'seconds_since_epoch' in shard_results_list[0]:
+    return _merge_json_test_result_format(shard_results_list)
+  else:
+    return _merge_simplified_json_format(shard_results_list)
+
+
+def _merge_simplified_json_format(shard_results_list):
+  # This code is specialized to the "simplified" JSON format that used to be
+  # the standard for recipes.
+
+  # These are the only keys we pay attention to in the output JSON.
+  merged_results = {
+    'successes': [],
+    'failures': [],
+    'valid': True,
+  }
+
+  for result_json in shard_results_list:
+    successes = result_json.get('successes', [])
+    failures = result_json.get('failures', [])
+    valid = result_json.get('valid', True)
+
+    if (not isinstance(successes, list) or not isinstance(failures, list) or
+        not isinstance(valid, bool)):
+      raise Exception(
+        'Unexpected value type in %s' % result_json)  # pragma: no cover
+
+    merged_results['successes'].extend(successes)
+    merged_results['failures'].extend(failures)
+    merged_results['valid'] = merged_results['valid'] and valid
+  return merged_results
+
+
+def _merge_json_test_result_format(shard_results_list):
+  # This code is specialized to the Chromium JSON test results format version 3:
+  # https://www.chromium.org/developers/the-json-test-results-format
+
+  # These are required fields for the JSON test result format version 3.
+  merged_results = {
+    'tests': {},
+    'interrupted': False,
+    'path_delimiter': '',
+    'version': 3,
+    'seconds_since_epoch': float('inf'),
+    'num_failures_by_type': {
+    }
+  }
+  # To make sure that we don't mutate existing shard_results_list.
+  shard_results_list = copy.deepcopy(shard_results_list)
+  for result_json in shard_results_list:
+    if not ('tests' in result_json and
+            'interrupted' in result_json and
+            'path_delimiter' in result_json and
+            'version' in result_json and
+            'seconds_since_epoch' in result_json and
+            'num_failures_by_type' in result_json):
+      raise Exception('Invalid json test results')
+
+    # Traverse the result_json's test trie & merged_results's test tries in
+    # DFS order & add the n to merged['tests'].
+    curr_result_nodes_queue = [result_json['tests']]
+    merged_results_nodes_queue = [merged_results['tests']]
+    while curr_result_nodes_queue:
+      curr_node = curr_result_nodes_queue.pop()
+      merged_node = merged_results_nodes_queue.pop()
+      for k, v in curr_node.iteritems():
+        if k in merged_node:
+          curr_result_nodes_queue.append(v)
+          merged_results_nodes_queue.append(merged_node[k])
+        else:
+          merged_node[k] = v
+
+    # Update the rest of the fields for merged_results.
+    merged_results['interrupted'] |= result_json['interrupted']
+    if not merged_results['path_delimiter']:
+      merged_results['path_delimiter'] = result_json['path_delimiter']
+    elif merged_results['path_delimiter'] != result_json['path_delimiter']:
+      raise Exception(  # pragma: no cover - covered by results_merger_unittest
+          'Incosistent path delimiter: %s %s' %
+          (merged_results['path_delimiter'],
+           result_json['path_delimiter']))
+    if result_json['version'] != 3:
+      raise Exception(  # pragma: no cover - covered by results_merger_unittest
+          'Only version 3 of json test result format is supported')
+    merged_results['seconds_since_epoch'] = min(
+        merged_results['seconds_since_epoch'],
+        result_json['seconds_since_epoch'])
+    for result_type, count in result_json['num_failures_by_type'].iteritems():
+      merged_results['num_failures_by_type'].setdefault(result_type, 0)
+      merged_results['num_failures_by_type'][result_type] += count
+  return merged_results