exec git init
exec git config user.email i@example.com
exec git config user.name someone
exec git checkout -b main

exec git add file
exec git commit -m 'commit'
exec sed -i 3d file

exec sed -i '4 anewline' file
exec cat file

exec git diff --shortstat
stdout '1 file changed, 1 insertion\(\+\), 1 deletion\(-\)'

env WANT_STATUS='NumModified=1 LocalBranch=main HEAD=[a-f0-9]{7} State=Default Insertions=1 Deletions=1'
gitstatus
! stderr .

-- file --
line1

line2

line3