Improve tool that analyzes gm JSON summary

gm/display_json_results.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
-"""Utility to confirm that a JSON summary written by GM contains no failures.
+"""Utility to display a summary of JSON-format GM results, and exit with
+a nonzero errorcode if there were non-ignored failures in the GM results.
 
 Usage:
-  python confirm_no_failures_in_json.py <filename>
+  python display_json_results.py <filename>
+
+TODO(epoger): We may want to add flags to set the following:
+- which error types cause a nonzero return code
+- maximum number of tests to list for any one ResultAccumulator
+  (to keep the output reasonably short)
 """
 
 __author__ = 'Elliot Poger'
 
 
 import json
 import sys
 
 
 # These constants must be kept in sync with the kJsonKey_ constants in
 # gm_expectations.cpp !
 JSONKEY_ACTUALRESULTS = 'actual-results'
 JSONKEY_ACTUALRESULTS_FAILED = 'failed'
-
-# This is the same indent level as used by jsoncpp, just for consistency.
-JSON_INDENTLEVEL = 3
+JSONKEY_ACTUALRESULTS_FAILUREIGNORED = 'failure-ignored'
+JSONKEY_ACTUALRESULTS_NOCOMPARISON = 'no-comparison'
+JSONKEY_ACTUALRESULTS_SUCCEEDED = 'succeeded'
 
 
-def Assert(filepath):
-  """Raises an exception if the JSON summary at filepath contains any failed
-  tests, or if we were unable to read the JSON summary."""
-  failed_tests = GetFailedTests(filepath)
-  if failed_tests:
-    raise Exception('JSON file %s contained these test failures...\n%s' % (
-        filepath, json.dumps(failed_tests, indent=JSON_INDENTLEVEL)))
+class ResultAccumulator(object):
+  """Object that accumulates results of a given type, and can generate a
+     summary upon request."""
+
+  def __init__(self, name, do_list, do_fail):
+    """name: name of the category this result type falls into
+       do_list: whether to list all of the tests with this results type
+       do_fail: whether to return with nonzero exit code if there are any
+                results of this type
+    """
+    self._name = name
+    self._do_list = do_list
+    self._do_fail = do_fail
+    self._testnames = []
+
+  def AddResult(self, testname):
+    """Adds a result of this particular type.
+       testname: (string) name of the test"""
+    self._testnames.append(testname)
+
+  def ShouldSignalFailure(self):
+    """Returns true if this result type is serious (self._do_fail is True)
+       and there were any results of this type."""
+    if self._do_fail and self._testnames:
+      return True
+    else:
+      return False
+
+  def GetSummaryLine(self):
+    """Returns a single-line string summary of all results added to this
+       accumulator so far."""
+    summary = ''
+    if self._do_fail:
+      summary += '[*] '
+    else:
+      summary += '[ ] '
+    summary += str(len(self._testnames))
+    summary += ' '
+    summary += self._name
+    if self._do_list:
+      summary += ': '
+      for testname in self._testnames:
+        summary += testname
+        summary += ' '
+    return summary
 
 
-def GetFailedTests(filepath):
-  """Returns the dictionary of failed tests from the JSON file at filepath."""
+def Display(filepath):
+  """Displays a summary of the results in a JSON file.
+     Returns True if the results are free of any significant failures.
+     filepath: (string) path to JSON file"""
+
+  # Map labels within the JSON file to the ResultAccumulator for each label.
+  results_map = {
+    JSONKEY_ACTUALRESULTS_FAILED:
+        ResultAccumulator(name='ExpectationsMismatch',
+                          do_list=True, do_fail=True),
+    JSONKEY_ACTUALRESULTS_FAILUREIGNORED:
+        ResultAccumulator(name='IgnoredExpectationsMismatch',
+                          do_list=True, do_fail=False),
+    JSONKEY_ACTUALRESULTS_NOCOMPARISON:
+        ResultAccumulator(name='MissingExpectations',
+                          do_list=False, do_fail=False),
+    JSONKEY_ACTUALRESULTS_SUCCEEDED:
+        ResultAccumulator(name='Passed',
+                          do_list=False, do_fail=False),
+  }
+
+  success = True
   json_dict = json.load(open(filepath))
   actual_results = json_dict[JSONKEY_ACTUALRESULTS]
-  return actual_results[JSONKEY_ACTUALRESULTS_FAILED]
+  for label, accumulator in results_map.iteritems():
+    results = actual_results[label]
+    if results:
+      for result in results:
+        accumulator.AddResult(result)
+    print accumulator.GetSummaryLine()
+    if accumulator.ShouldSignalFailure():
+      success = False
+  print '(results marked with [*] will cause nonzero return value)'
+  return success
 
 
 if '__main__' == __name__:
   if len(sys.argv) != 2:
     raise Exception('usage: %s <input-json-filepath>' % sys.argv[0])
-  Assert(sys.argv[1])
+  sys.exit(0 if Display(sys.argv[1]) else 1)