test_cmp_rev HEAD burble
'
+test_expect_success '"add" with <branch> omitted' '
+ git worktree add wiffle/bat &&
+ test_cmp_rev HEAD bat
+'
+
+test_expect_success '"add" auto-vivify does not clobber existing branch' '
+ test_commit c1 &&
+ test_commit c2 &&
+ git branch precious HEAD~1 &&
+ test_must_fail git worktree add precious &&
+ test_cmp_rev HEAD~1 precious &&
+ test_path_is_missing precious
+'
+
test_done