Random seed generator for sharding_supervisor

tools/sharding_supervisor/sharding_supervisor.py

 #!/usr/bin/env python
 # Copyright (c) 2011 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.
 
 """Shards a given test suite and runs the shards in parallel.
 
 ShardingSupervisor is called to process the command line options and creates
 the specified number of worker threads. These threads then run each shard of
 the test in a separate process and report on the results. When all the shards
 have been completed, the supervisor reprints any lines indicating a test
 failure for convenience. If only one shard is to be run, a single subprocess
 is started for that shard and the output is identical to gtest's output.
 """
 
 
 from cStringIO import StringIO
 import optparse
 import os
 import pty
 import Queue
+import random
 import re
 import subprocess
 import sys
 import threading
 
 
 SS_USAGE = "Usage: python %prog [options] path/to/test [gtest_args]"
 SS_DEFAULT_NUM_CORES = 4
 SS_DEFAULT_SHARDS_PER_CORE = 5 # num_shards = cores * SHARDS_PER_CORE
 SS_DEFAULT_RUNS_PER_CORE = 1 # num_workers = cores * RUNS_PER_CORE
@@ skipping 253 matching lines @@
       " specified")
   parser.add_option(
       "--no-color", action="store_false", dest="color",
       help="disable color output")
   parser.add_option(
       "-s", "--runshard", type="int", help="single shard index to run")
   parser.add_option(
       "--reorder", action="store_true",
       help="ensure that all output from an earlier shard is printed before"
       " output from a later shard")
+  parser.add_option("--random-seed", action="store_true",
+      help="shuffle the tests with a random seed value")
   parser.disable_interspersed_args()
   (options, args) = parser.parse_args()
 
   if not args:
     parser.error("You must specify a path to test!")
   if not os.path.exists(args[0]):
     parser.error("%s does not exist!" % args[0])
 
   num_cores = DetectNumCores()
 
   if options.shards_per_core < 1:
     parser.error("You must have at least 1 shard per core!")
   num_shards = num_cores * options.shards_per_core
 
   if options.runs_per_core < 1:
     parser.error("You must have at least 1 run per core!")
   num_runs = num_cores * options.runs_per_core
 
   gtest_args = ["--gtest_color=%s" % {
       True: "yes", False: "no"}[options.color]] + args[1:]
 
+  if options.random_seed:
+    seed = random.randint(1, 99999)
+    gtest_args.extend(["--gtest_shuffle", "--gtest_random_seed=%i" % seed])
+
   if options.runshard != None:
     # run a single shard and exit
     if (options.runshard < 0 or options.runshard >= num_shards):
       parser.error("Invalid shard number given parameters!")
     shard = RunShard(
         args[0], num_shards, options.runshard, gtest_args, None, None)
     shard.communicate()
     return shard.poll()
 
   # shard and run the whole test
   ss = ShardingSupervisor(args[0], num_shards, num_runs, options.color,
                           options.reorder, gtest_args)
   return ss.ShardTest()
 
 
 if __name__ == "__main__":
   sys.exit(main())