autoninja: add simple test

This is to prevent revert like https://crrev.com/c/3607513

Bug: 1317620
Change-Id: I6ab7aba5f92719bd573d22d90358f58e48aeb10c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3607514Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>

PRESUBMIT.py

@@ -124,7 +124,10 @@ def CheckUnitTestsOnCommit(input_api, output_api):
       'recipes_test.py',
   ]
 
-  py3_only_tests = ['ninjalog_uploader_test.py']
+  py3_only_tests = [
+      'autoninja_test.py',
+      'ninjalog_uploader_test.py',
+  ]
 
   tests = input_api.canned_checks.GetUnitTestsInDirectory(
       input_api,

tests/OWNERS

+per-file autoninja_test.py=brucedawson@chromium.org
+per-file autoninja_test.py=tikuta@chromium.org
 per-file ninjalog_uploader_test.py=tikuta@chromium.org

tests/autoninja_test.py

+#!/usr/bin/env python3
+# Copyright (c) 2022 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.
+
+import multiprocessing
+import os
+import os.path
+import sys
+import unittest
+import unittest.mock
+
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.insert(0, ROOT_DIR)
+
+import autoninja
+
+
+class AutoninjaTest(unittest.TestCase):
+  def test_autoninja(self):
+    autoninja.main([])
+
+  def test_autoninja_goma(self):
+    with unittest.mock.patch(
+        'os.path.exists',
+        return_value=True) as mock_exists, unittest.mock.patch(
+            'autoninja.open', unittest.mock.mock_open(
+                read_data='use_goma=true')) as mock_open, unittest.mock.patch(
+                    'subprocess.call', return_value=0):
+      args = autoninja.main([]).split()
+      mock_exists.assert_called()
+      mock_open.assert_called_once()
+
+    self.assertIn('-j', args)
+    parallel_j = int(args[args.index('-j') + 1])
+    self.assertGreater(parallel_j, multiprocessing.cpu_count())
+
+
+if __name__ == '__main__':
+  unittest.main()