unittests: Add tests for tv_list_find*() functions

Additional modifications:

- More `const` qualifiers in tested functions.
- `tv_list_find_str()` second argument is more in-line with other
  `tv_list_find*()` functions.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 7c3754607e..d5624f354a 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -21783,7 +21783,7 @@ void ex_oldfiles(exarg_T *eap)
       nr = prompt_for_number(false);
       msg_starthere();
       if (nr > 0 && nr <= l->lv_len) {
-        const char *const p = tv_list_find_str(l, nr);
+        const char *const p = tv_list_find_str(l, nr - 1);
         if (p == NULL) {
           return;
         }