buffer: add documentation for string_mod and extend related UT
Since I was confused what exactly string_mod does, I
added documentation and additional UTs to make it
clearer.
Change-Id: I911fb5c5fa4b41f1fc1a30c6bf8b314245f64a6e
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Arne Schwabe <arne-openvpn@rfc2549.org>
Message-Id: <
20231211170214.85417-1-frank@lichtenheld.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg27761.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>