Here are the failing GNU tests as of 2025-11-03
I hope to complete this issue, either by fixing tests, or at least providing a reason explaining what's missing in our implementation.

https://uutils.github.io/coreutils/docs/test_coverage.html

Replace #4627

FAILED

• basenc
  • base64.pl
  • basenc.pl
• cat
  • cat-self.sh (fix(cat): refine unsafe overwrite detection for appending files #9122)
• cksum
  • b2sum.sh
  • cksum.sh (reason: missing --debug option)
• cp
  • cp-a-selinux.sh
  • link_heap.sh
  • preserve-gid.sh
• date
  • date.pl
  • date-debug.sh
• dd
  • no-allocate.sh
  • nocache_eof.sh
  • nocache_fail.sh
  • skip-seek-past-file.sh
  • stderr.sh
• du
  • files0-from.pl (du: handle --files0-from=- with piped in - #8985)
• env
  • env-signal-handler.sh
• fmt
  • non-space.sh
• fold
  • fold-characters.sh
  • fold-nbsp.sh
  • fold-zero-width.sh
  • fold.pl
• install
  • basic-1.sh
• ls
  • ls-misc.pl
  • stat-free-symlinks.sh
• misc
  • close-stdout.sh
  • nohup.sh
  • numfmt.pl
  • option-aliases.sh
  • stdbuf.sh
  • tee.sh
  • time-style.sh
  • tsort.pl
  • write-errors.sh
• od
  • od-float.sh
  • od.pl
• printf
  • printf-surprise.sh (printf: handle extremely large format widths gracefully to fix GNU test panic #9133)
• ptx
  • ptx-overrun.sh
  • ptx.pl
• readlink
  • readlink-posix.sh
• rm
  • one-file-system.sh
  • rm1.sh
• seq
  • seq-epipe.sh
• shred
  • shred-passes.sh
• sort
  • sort-continue.sh (fix(sort): GNU sort-continue.sh test #9107)
  • sort-debug-keys.sh
  • sort-debug-warn.sh
  • sort-field-limit.sh
  • sort-float.sh
  • sort-h-thousands-sep.sh
  • sort-merge-fdlimit.sh
  • sort-month.sh
  • sort.pl
• tac
  • tac-2-non-seekable.sh
• tail
  • follow-name.sh
  • follow-stdin.sh
  • inotify-rotate-resources.sh
  • overlay-headers.sh
  • pid-pipe.sh
  • pipe-f.sh
  • symlink.sh
  • tail.pl
• tty
  • tty-eof.pl
• wc
  • wc-cpu.sh

SKIPPED

• cp
  • cp-mv-enotsup-xattr.sh
  • nfs-removal-race.sh
• csplit
  • csplit-io-err.sh
• date (ci: add locales for GNU tests #9052 moves the date-<country>.sh tests to failed)
  • date-ethiopia.sh (reason: Missing translation)
  • date-iran.sh (reason: Missing translation)
  • date-thailand.sh (reason: Missing translation)
• df
  • no-mtab-status.sh
  • skip-duplicates.sh
  • skip-rootfs.sh
• du
  • bigtime.sh
• id
  • gnu-zero-uids.sh
  • smack.sh
• misc
  • coreutils.sh (reason: meta test ?)
• mkdir
  • smack-no-root.sh
  • smack-root.sh
  • writable-under-readonly.sh
• mv
  • hardlink-case.sh
  • i-3.sh
• nproc
  • nproc-quota.sh
• pr
  • pr-tests.pl
• rm
  • fail-eperm.xpl
  • r-root.sh (reason: need root in the testsuite ?)
  • rm-readdir-fail.sh
• stty (reason: testsuite env not adapted ?)
  • bad-speed.sh
  • stty-invalid.sh
  • stty-pairs.sh
  • stty-row-col.sh
  • stty.sh
• tac
  • tac-continue.sh
• tail
  • inotify-dir-recreate.sh
  • inotify-race.sh
  • inotify-race2.sh
• timeout
  • timeout-group.sh