fix: harden rsyncshot destination, rotation, and mount handling

Refuse to run when REMOTE_PATH or MOUNTDIR is empty or non-absolute. A blank config value otherwise resolves the destination to the filesystem root, where rotation runs rm -rf and --delete.

Run the rotation cp/mv/rm as bare command names in remote mode, resolved by the remote PATH, instead of hardcoded /usr/bin paths that broke on remotes whose binaries live elsewhere. Resolve the real binary via command -v in local mode.

Pass rsync -R so each source is stored under its full path. Two includes sharing a basename (/usr/local/bin and /usr/bin) previously both mapped to latest/bin, and the second sync's --delete wiped the first. This changes the stored layout: /usr/local/bin now lives at latest/usr/local/bin instead of latest/bin. /home and /etc are unchanged.

Add rsync --numeric-ids so /etc and /home ownership survives a restore when the destination has a different passwd/group database.

Match mount points exactly via is_mounted() instead of a substring grep of /proc/mounts, so /media/backup no longer matches /media/backup2, paths compare literally, and mount points with spaces work.

Reject a retention count below 1, which previously still created one snapshot. Drop the grep "|| echo 0" that emitted a stray second line, assemble ssh options as arrays, and quote the RSYNC_RSH identity path.

Extract derive_paths() and is_mounted() as sourceable functions and add unit, rsync-flag, and gated remote-mode test suites. The suite now runs 36 tests, and shellcheck is clean across the script and tests.

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/test_rsyncshot.sh b/tests/test_rsyncshot.sh
index 15f2a99..95a0032 100755
--- a/tests/test_rsyncshot.sh
+++ b/tests/test_rsyncshot.sh
@@ -22,6 +22,7 @@ QUICK=false
 while [[ $# -gt 0 ]]; do
     case $1 in
         -v|--verbose)
+            # shellcheck disable=SC2034  # reserved flag; verbose output not yet wired
             VERBOSE=true
             shift
             ;;
@@ -90,12 +91,15 @@ run_test_file() {
 
 # Run test suites
 run_test_file "$SCRIPT_DIR/cases/test_validation.sh" "validation"
+run_test_file "$SCRIPT_DIR/cases/test_functions.sh" "functions"
 run_test_file "$SCRIPT_DIR/cases/test_includes.sh" "includes"
 run_test_file "$SCRIPT_DIR/cases/test_dryrun.sh" "dryrun"
+run_test_file "$SCRIPT_DIR/cases/test_rsync_flags.sh" "rsync_flags"
 
 if [ "$QUICK" = false ]; then
     run_test_file "$SCRIPT_DIR/cases/test_backup.sh" "backup"
     run_test_file "$SCRIPT_DIR/cases/test_cron.sh" "cron"
+    run_test_file "$SCRIPT_DIR/cases/test_remote.sh" "remote"
 else
     echo ""
     echo "Skipping slow tests (backup, cron) - use without --quick to run all"