fix(custom-ordering): preserve the trailing newline in reverse and number

cj/reverse-lines and cj/number-lines split the region on newlines without accounting for a trailing one, so it became a spurious empty element. Reversing "a\nb\n" floated that empty to the top ("\nb\na"), and numbering added a phantom final numbered line. Both now strip a trailing newline before splitting and reattach it after, matching cj/--arrayify, while preserving internal blank lines. Corrected the two tests that asserted the broken output.

1 files changed, 4 insertions, 2 deletions

diff --git a/tests/test-custom-ordering-reverse-lines.el b/tests/test-custom-ordering-reverse-lines.el
index 3c71362d..5b8c01ac 100644
--- a/tests/test-custom-ordering-reverse-lines.el
+++ b/tests/test-custom-ordering-reverse-lines.el
@@ -86,9 +86,11 @@ Returns the transformed string."
     (should (string= result "b\n\na"))))
 
 (ert-deftest test-reverse-lines-trailing-newline ()
-  "Should handle trailing newline."
+  "Should reverse the lines and preserve the trailing newline.
+The old split dropped the trailing newline into a leading empty line,
+producing \"\\nline2\\nline1\"."
   (let ((result (test-reverse-lines "line1\nline2\n")))
-    (should (string= result "\nline2\nline1"))))
+    (should (string= result "line2\nline1\n"))))
 
 (ert-deftest test-reverse-lines-only-newlines ()
   "Should reverse lines that are only newlines."