Add test for tag pushing in push-to-trunk script.

Add test for tag pushing in push-to-trunk script.

BUG=chromium:410721
LOG=n
TEST=script_test.py
TBR=tandrii@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=24468

[Michael Achenbach, 2014-10-08 13:05:18]

machenbach@chromium.org changed reviewers:
+ tandrii@chromium.org

[Michael Achenbach, 2014-10-08 13:07:40]

PTAL

https://codereview.chromium.org/641633002/diff/1/tools/push-to-trunk/test_scr...
File tools/push-to-trunk/test_scripts.py (right):

https://codereview.chromium.org/641633002/diff/1/tools/push-to-trunk/test_scr...
tools/push-to-trunk/test_scripts.py:845: def testPushToTrunkForcedNewGit(self):
This is a dirty c/p from the test above. The old version will eventually go away
- therefore I don't want to invest time into modularization.

https://codereview.chromium.org/641633002/diff/1/tools/push-to-trunk/test_scr...
tools/push-to-trunk/test_scripts.py:951: "--vc-interface", "git_read_svn_write",
"-f",
The git tagging is still behind the flag --vc-interface git_read_svn_write. When
set, all the git expectations should use the new workflow on the git mirror.

[Michael Achenbach, 2014-10-08 13:36:39]

Committed patchset #1 (id:1) manually as 24468 (tree was closed).

[tandrii(chromium), 2014-10-08 17:13:02]

lgtm