Let the test mapping updater make commits and upload changes.

This will make it easier to run it on many crates and upload all of
the changes.  It puts the uploaded CLs in a topic to save resources.
If the script does not change a TEST_MAPPING, it does not upload
anything.

Test: Run on a subset of crates.
Change-Id: I47b4756d968c54d7d810c8a19a8a7419aebc6e15

scripts/update_crate_tests.py

@@ -34,6 +34,7 @@ import os
 import platform
 import subprocess
 import sys
+from datetime import datetime
 from pathlib import Path
 
 # Some tests requires specific options. Consider fixing the upstream crate
@@ -250,10 +251,15 @@ class TestMapping(object):
 
 def parse_args():
     parser = argparse.ArgumentParser('update_crate_tests')
-    parser.add_argument(
-        'paths',
-        nargs='*',
-        help='Absolute or relative paths of the projects as globs.')
+    parser.add_argument('paths',
+                        nargs='*',
+                        help='Absolute or relative paths of the projects as globs.')
+    parser.add_argument('--branch_and_commit',
+                        action='store_true',
+                        help='Starts a new branch and commit changes.')
+    parser.add_argument('--push_change',
+                        action='store_true',
+                        help='Pushes change to Gerrit.')
     return parser.parse_args()
 
 
@@ -270,9 +276,20 @@ def main():
     for path in paths:
         try:
             test_mapping = TestMapping(env, bazel, path)
-        except UpdaterException as err:
+            test_mapping.create()
+            changed = (subprocess.call(['git', 'diff', '--quiet']) == 1)
+            if changed and args.branch_and_commit:
+                subprocess.check_output(['repo', 'start',
+                                         'tmp_auto_test_mapping', '.'])
+                subprocess.check_output(['git', 'add', 'TEST_MAPPING'])
+                subprocess.check_output(['git', 'commit', '-m',
+                                         'Update TEST_MAPPING\n\nTest: None'])
+            if changed and args.push_change:
+                date = datetime.today().strftime('%m-%d')
+                subprocess.check_output(['git', 'push', 'aosp', 'HEAD:refs/for/master',
+                                         '-o', 'topic=test-mapping-%s' % date])
+        except (UpdaterException, subprocess.CalledProcessError) as err:
             sys.exit("Error: " + str(err))
-        test_mapping.create()
 
 if __name__ == '__main__':
   main()