i have core.abbrev set to 12 in my ~/.gitconfig and this breaks the unittest.  i tried tweaking depot_tools/.git/config but that didn't help.

tests/git_common_test.py (5.91s) failed
................F..............uCannot foo with a dirty tree. You must commit locally first.
Uncommitted files: (git diff-index --name-status HEAD)
A       test.file
/tmp/git_repo0S6T_tbase/tmpcvroGf
.......
======================================================================
FAIL: testBlame (__main__.GitReadOnlyFunctionsTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "tests/git_common_test.py", line 297, in testBlame
    'tag_D').split('\n'))
AssertionError: Lists differ: ['435b19bc (Author McAuthorly ... != ['435b19bc9ddc6 (Author McAuth...

First differing element 0:
435b19bc (Author McAuthorly 1970-01-05 00:00:00 +0000 1) file2 - vanilla
435b19bc9ddc6 (Author McAuthorly 1970-01-05 00:00:00 +0000 1) file2 - vanilla

- ['435b19bc (Author McAuthorly 1970-01-05 00:00:00 +0000 1) file2 - vanilla',
+ ['435b19bc9ddc6 (Author McAuthorly 1970-01-05 00:00:00 +0000 1) file2 - vanilla',
?           +++++

-  '33abbc0a (Author McAuthorly 1970-01-07 00:00:00 +0000 2) file2 - merged']
+  '33abbc0a63319 (Author McAuthorly 1970-01-07 00:00:00 +0000 2) file2 - merged']
?           +++++


----------------------------------------------------------------------
Ran 39 tests in 5.756s

FAILED (failures=1, unexpected successes=1)