Fix swarming tests not running in parallel

Due to recent Chrome infra changes in
https://chromium-review.googlesource.com/c/472290/
tests running on swarming are now assumed to emit JSON results
or will be marked as failing. This requires us to use our
gtest-parallel wrapper for all our Swarming tests
(or implement the --isolated-script-test-output flag, which
normally only is implemented by the Chromium test launcher).

The low_bandwidth_audio_test can actually run in parallel,
so just change that.

The webrtc_nonparallel_tests cannot, so this CL changes MB
to pass --workers=1 flag to gtest-parallel, which makes the
tests run in sequence. This adds a little confusion but the root
problem is really that our gtest-parallel script [1] does a lot more
than just running the tests in parallel these days, so it should
probably be renamed.

Also make sure gtest-parallel-wrapper.py [2] consumes the
--isolated-script-test-chartjson-output flag (unused) so we don't
pass it on to the test executable.

[1]: https://chromium.googlesource.com/external/github.com/google/gtest-parallel/+/master/gtest-parallel
[2]: https://chromium.googlesource.com/external/webrtc/+/master/tools-webrtc/gtest-parallel-wrapper.py

BUG=709988
[email protected]
NOTRY=True

Review-Url: https://codereview.webrtc.org/2806373002
Cr-Commit-Position: refs/heads/master@{#17646}

Author: kjellander

tools-webrtc/gtest-parallel-wrapper.py

@@ -59,6 +59,11 @@ def main():
 
   parser = argparse.ArgumentParser()
   parser.add_argument('--isolated-script-test-output', type=str, default=None)
+
+  # TODO(ehmaldonado): Implement this flag instead of just "eating" it.
+  parser.add_argument('--isolated-script-test-chartjson-output', type=str,
+                      default=None)
+
   parser.add_argument('--output_dir', type=str, default=None)
   parser.add_argument('--timeout', type=int, default=None)
 

tools-webrtc/mb/gn_isolate_map.pyl

@@ -49,7 +49,7 @@
   },
   "low_bandwidth_audio_test": {
     "label": "//webrtc/audio:low_bandwidth_audio_test",
-    "type": "non_parallel_console_test_launcher",
+    "type": "console_test_launcher",
     "args": [
       "--quick",
     ],

tools-webrtc/mb/mb.py

@@ -1087,9 +1087,7 @@ def GetIsolateCommand(self, target, vals):
           '--test',
       ]
 
-      gtest_parallel = (test_type != 'non_parallel_console_test_launcher' and
-                        not memcheck)
-      if gtest_parallel:
+      if not memcheck:
         extra_files += [
             '../../third_party/gtest-parallel/gtest-parallel',
             '../../tools-webrtc/gtest-parallel-wrapper.py',
@@ -1111,17 +1109,19 @@ def GetIsolateCommand(self, target, vals):
 
       cmdline = (['../../testing/xvfb.py'] if xvfb else
                  ['../../testing/test_env.py'])
-      if memcheck:
-        cmdline += memcheck_cmdline
-      elif gtest_parallel:
-        cmdline += gtest_parallel_wrapper
-      cmdline += [
-          executable,
+      cmdline += memcheck_cmdline if memcheck else gtest_parallel_wrapper
+      cmdline.append(executable)
+      if test_type == 'non_parallel_console_test_launcher' and not memcheck:
+        # Still use the gtest-parallel-wrapper.py script since we need it to
+        # run tests on swarming, but don't execute tests in parallel.
+        cmdline.append('--workers=1')
+
+      cmdline.extend([
           '--',
           '--asan=%d' % asan,
           '--msan=%d' % msan,
           '--tsan=%d' % tsan,
-      ]
+      ])
 
     cmdline += isolate_map[target].get('args', [])
 

tools-webrtc/mb/mb_unittest.py

@@ -441,11 +441,16 @@ def test_gn_gen_non_parallel_console_test_launcher(self):
 
     self.assertEqual(files, [
         '../../testing/test_env.py',
+        '../../third_party/gtest-parallel/gtest-parallel',
+        '../../tools-webrtc/gtest-parallel-wrapper.py',
         'base_unittests',
     ])
     self.assertEqual(command, [
         '../../testing/test_env.py',
+        '../../tools-webrtc/gtest-parallel-wrapper.py',
+        '--output_dir=${ISOLATED_OUTDIR}/test_logs',
         './base_unittests',
+        '--workers=1',
         '--',
         '--asan=0',
         '--msan=0',