Updating benchmark script to only write chartjson when flag present.

testing/scripts/run_telemetry_benchmark_as_googletest.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 """Runs an isolate bundled Telemetry benchmark.
 
 This script attempts to emulate the contract of gtest-style tests
 invoked via recipes. The main contract is that the caller passes the
 argument:
@@ skipping 26 matching lines @@
 # Importing it and using its get_sandbox_env breaks test runs on Linux
 # (it seems to unset DISPLAY).
 CHROME_SANDBOX_ENV = 'CHROME_DEVEL_SANDBOX'
 CHROME_SANDBOX_PATH = '/opt/chromium/chrome_sandbox'
 
 def main():
   parser = argparse.ArgumentParser()
   parser.add_argument(
       '--isolated-script-test-output', type=argparse.FileType('w'),
       required=True)
-  parser.add_argument(
-    '--isolated-script-test-chartjson-output', type=argparse.FileType('w'),
-    required=False)
+  # Only create the chartjson directory if this test is producing chartjson
+  # results.  Otherwise, remove from the argument list.
+  writing_chartjson_results = '--output-format=chartjson' in sys.argv
+  if writing_chartjson_results:
+    parser.add_argument(
+      '--isolated-script-test-chartjson-output', type=argparse.FileType('w'),
+      required=False)
+  else:
+    for arg in sys.argv:
+      if 'isolated-script-test-chartjson-output' in arg:
+        sys.argv.remove(arg)
+        break

[Ken Russell (switch to Gerrit), 2016/09/22 20:31:48]

Instead of this somewhat contorted code, could you just change the
parser.add_argument call to use type=str, and open the file yourself lazily
below? I think that would be more maintainable.

[eyaich1, 2016/09/23 13:52:38]

Done.

   parser.add_argument('--xvfb', help='Start xvfb.', action='store_true')
   args, rest_args = parser.parse_known_args()
   xvfb_proc = None
   openbox_proc = None
   xcompmgr_proc = None
   env = os.environ.copy()
   # Assume we want to set up the sandbox environment variables all the
   # time; doing so is harmless on non-Linux platforms and is needed
   # all the time on Linux.
   env[CHROME_SANDBOX_ENV] = CHROME_SANDBOX_PATH
   if args.xvfb and xvfb.should_start_xvfb(env):
     xvfb_proc, openbox_proc, xcompmgr_proc = xvfb.start_xvfb(env=env,
                                                              build_dir='.')
     assert xvfb_proc and openbox_proc and xcompmgr_proc, 'Failed to start xvfb'
   try:
     tempfile_dir = tempfile.mkdtemp('telemetry')
     valid = True
     failures = []
-    chartjson = (args.isolated_script_test_chartjson_output is not None and
-      '--output-format=chartjson' in rest_args)
+    chartjson = (writing_chartjson_results
+      and args.isolated_script_test_chartjson_output is not None)
     chartresults = None
     try:
       rc = common.run_command([sys.executable] + rest_args + [
         '--output-dir', tempfile_dir,
         '--output-format=json'
       ], env=env)
       tempfile_name = os.path.join(tempfile_dir, 'results.json')
       with open(tempfile_name) as f:
         results = json.load(f)
       for value in results['per_page_values']:
@@ skipping 41 matching lines @@
 
 if __name__ == '__main__':
   # Conform minimally to the protocol defined by ScriptTest.
   if 'compile_targets' in sys.argv:
     funcs = {
       'run': None,
       'compile_targets': main_compile_targets,
     }
     sys.exit(common.run_script(sys.argv[1:], funcs))
   sys.exit(main())