test_i18ngrep "invalid branch name" err
'
+test_expect_success 'branch -m with the initial branch' '
+ git init rename-initial &&
+ git -C rename-initial branch -m renamed &&
+ test renamed = $(git -C rename-initial symbolic-ref --short HEAD) &&
+ git -C rename-initial branch -m renamed again &&
+ test again = $(git -C rename-initial symbolic-ref --short HEAD)
+'
+
test_done