tests: avoid git diffstat singular/plural output difference 'git diff --stat' output changed with regard to the amount of changes/insertions/deletions shown. In older git versions (1.7.7.6), output was shown as: 2 files changed, 2 insertions(+), 1 deletions(-) In newer versions, output is shown as: 2 files changed, 2 insertions(+), 1 deletion(-) This patch uses a regex to handle both cases.