While re-reading the code, I thought I had found a bug but I hadn't. So I wrote
the test to document the behavior to not make the same error again.

R=dpranke@chromium.org
BUG=
TEST=


Review URL: http://codereview.chromium.org/8121001

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@103772 0039d316-1c4b-4281-b951-d872f2087c98