Change run_webkit_tests default order to random on Linux and Mac

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 # Copyright (C) 2010 Gabor Rapcsanyi (rgabor@inf.u-szeged.hu), University of Szeged
 # Copyright (C) 2011 Apple Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
@@ skipping 311 matching lines @@
                 default=0,
                 help="Set the maximum number of locked shards"),
             optparse.make_option(
                 "--nocheck-sys-deps",
                 action="store_true",
                 default=False,
                 help="Don't check the system dependencies (themes)"),
             optparse.make_option(
                 "--order",
                 action="store",
-                default="natural",
+                default="random",

[qyearsley, 2016/12/14 17:58:21]

In order to temporarily keep it as "natural" by default on Windows, you could
change this to something like:

  default=("natural" if sys.platform == "win32" else "random")

Or, more verbosely but not requiring importing sys:

  default=("natural" if self.host.port_factory.get().port_name == "win" else
"random")

And add a TODO note making a reference to crbug.com/601332.

[jeffcarp, 2016/12/14 18:07:46]

Thank you so much for this!! I was worrying about how to find out how to filter
by platform in webkitpy.

                 help=("Determine the order in which the test cases will be run. "
                       "'none' == use the order in which the tests were listed "
                       "either in arguments or test list, "
                       "'natural' == use the natural order (default), "

[qyearsley, 2016/12/14 17:58:21]

This help text should be updated.

                       "'random' == pseudo-random order. Seed can be specified "
                       "via --seed, otherwise it will default to the current unix timestamp.")),
             optparse.make_option(
                 "--profile",
                 action="store_true",
                 help="Output per-test profile information."),
             optparse.make_option(
                 "--profiler",
                 action="store",
                 help="Output per-test profile information, using the specified profiler."),
@@ skipping 239 matching lines @@
             _log.debug("\t%s", process)
 
         return run_details
 
     finally:
         printer.cleanup()
 
 if __name__ == '__main__':
     exit_code = main(sys.argv[1:], sys.stdout, sys.stderr)
     sys.exit(exit_code)