Add --test to gen_tasks.go, add presubmit check

PRESUBMIT.py

 # 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.
 
 
 """Top-level presubmit script for Skia.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
@@ skipping 165 matching lines @@
 
   recipes_py = os.path.join('infra', 'bots', 'recipes.py')
   cmd = ['python', recipes_py, 'simulation_test']
   try:
     subprocess.check_output(cmd)
   except subprocess.CalledProcessError as e:
     results.append(output_api.PresubmitError(
         '`%s` failed:\n%s' % (' '.join(cmd), e.output)))
   return results
 
+
+def _GenTasksTest(input_api, output_api):
+  """Run gen_tasks.go test."""
+  results = []
+  if not any(f.LocalPath().startswith('infra')
+             for f in input_api.AffectedFiles()):
+    return results
+
+  gen_tasks = os.path.join('infra', 'bots', 'gen_tasks.go')
+  cmd = ['go', 'run', gen_tasks, '--test']
+  try:
+    subprocess.check_output(cmd)
+  except subprocess.CalledProcessError as e:
+    results.append(output_api.PresubmitError(
+        '`%s` failed:\n%s' % (' '.join(cmd), e.output)))
+  return results
+
+
 def _CheckGNFormatted(input_api, output_api):
   """Make sure any .gn files we're changing have been formatted."""
   results = []
   for f in input_api.AffectedFiles():
     if not f.LocalPath().endswith('.gn'):
       continue
 
     cmd = ['gn', 'format', '--dry-run', f.LocalPath()]
     try:
       subprocess.check_output(cmd)
@@ skipping 31 matching lines @@
 
 def CheckChangeOnUpload(input_api, output_api):
   """Presubmit checks for the change on upload.
 
   The following are the presubmit checks:
   * Check change has one and only one EOL.
   """
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   # Run on upload, not commit, since the presubmit bot apparently doesn't have
-  # coverage installed.
+  # coverage or Go installed.
   results.extend(_RecipeSimulationTest(input_api, output_api))
+  results.extend(_GenTasksTest(input_api, output_api))

[borenet, 2016/10/04 18:59:47]

This is really unfortunate. We need to be able to test these on the CQ.

[dogben, 2016/10/04 19:16:23]

Is there a reason skia_presubmit-Trybot doesn't run on swarming (or
swarmbucket)?

[borenet, 2016/10/04 19:26:55]

That bot was brought up by chrome-infra after they turned off presubmit checks
on the CQ itself. It's running a non-skia recipe
(https://chromium.googlesource.com/chromium/tools/build/+/master/scripts/slave...),
and I had previously dismissed it as not under our control. I guess all that
matters is that we run the presubmit on a trybot somewhere, so we could possibly
create our own presubmit recipe, add a bot which runs that in Swarming, and then
turn the current presubmit bot off.

[borenet, 2016/10/04 19:32:22]

Filed https://bugs.chromium.org/p/skia/issues/detail?id=5823

+
   results.extend(_CheckGNFormatted(input_api, output_api))
   return results
 
 
 def _CheckTreeStatus(input_api, output_api, json_url):
   """Check whether to allow commit.
 
   Args:
     input_api: input related apis.
     output_api: output related apis.
@@ skipping 355 matching lines @@
     state and an error if it is in 'Closed' state.
   """
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(
       _CheckTreeStatus(input_api, output_api, json_url=(
           SKIA_TREE_STATUS_URL + '/banner-status?format=json')))
   results.extend(_CheckLGTMsForPublicAPI(input_api, output_api))
   results.extend(_CheckOwnerIsInAuthorsFile(input_api, output_api))
   return results