Initial pre-release

tmux-party: share a tmux session with people on the same UNIX host.
Single-file POSIX shell (party) with a filesystem + tmux server-access
trust model. See README.md.

tests/20-helpers.bats

@@ -0,0 +1,96 @@
+#!/usr/bin/env bats
+
+load 'helpers'
+
+setup() {
+  setup_party_sandbox
+  load_party_lib
+}
+
+# party name validation
+# =====================
+
+@test "validate_party_name accepts plain names" {
+  validate_party_name "debug-the-deploy"
+  validate_party_name "mob_coding"
+  validate_party_name "p"
+  validate_party_name "Party-2026"
+}
+
+@test "validate_party_name rejects empty" {
+  run validate_party_name ""
+  [ "$status" -ne 0 ]
+}
+
+@test "validate_party_name rejects path separators" {
+  run validate_party_name "../etc"
+  [ "$status" -ne 0 ]
+  run validate_party_name "a/b"
+  [ "$status" -ne 0 ]
+}
+
+@test "validate_party_name rejects names over 63 chars" {
+  long=$(printf 'a%.0s' $(seq 1 64))
+  run validate_party_name "$long"
+  [ "$status" -ne 0 ]
+}
+
+@test "validate_party_name rejects whitespace and shell metas" {
+  for bad in "a b" "a;b" 'a$b' 'a`b' "a'b" 'a"b'; do
+    run validate_party_name "$bad"
+    [ "$status" -ne 0 ] || { echo "should have rejected: $bad"; false; }
+  done
+}
+
+# time
+# ====
+
+@test "iso_now produces ISO 8601 UTC with Z suffix" {
+  out=$(iso_now)
+  case "$out" in
+    [0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]T[0-9][0-9]:[0-9][0-9]:[0-9][0-9]Z) ;;
+    *) echo "bad timestamp: $out"; false ;;
+  esac
+}
+
+# user existence
+# ==============
+
+@test "user_exists returns 0 for the running user" {
+  user_exists "$USER"
+}
+
+@test "user_exists returns nonzero for a fictional user" {
+  ! user_exists "nonexistent_$(date +%s)_user"
+}
+
+# liveness
+# ========
+#
+# is_party_alive must not probe the PID with kill -0. POSIX kill(2) is
+# allowed to return EPERM when the caller can't signal the target, and
+# illumos/BSD/macOS honor that — so kill -0 against another user's PID
+# returns nonzero even when the process exists. Linux and Linux-ABI
+# zones (LX-branded) are the outliers that return 0; that's why the
+# bug hid in the test matrix until a native illumos run surfaced it.
+# Discovery now relies on `tmux -S list-clients` alone, which is
+# strictly stronger (filters PID-reuse, dead servers, AF_UNIX impostors).
+
+@test "is_party_alive does not reach for kill -0 (cross-user discovery)" {
+  body=$(declare -f is_party_alive)
+  [[ "$body" != *"kill "* ]] || { echo "$body"; false; }
+}
+
+@test "is_party_alive rejects non-numeric PID without invoking tmux" {
+  ! PARTY_TMUX=/nonexistent/should-not-be-called \
+      is_party_alive "" /tmp/should-not-matter
+  ! PARTY_TMUX=/nonexistent/should-not-be-called \
+      is_party_alive "abc" /tmp/should-not-matter
+}
+
+@test "is_party_alive returns nonzero when tmux server is absent" {
+  # Numeric PID, but no live tmux server at the socket path: tmux call
+  # fails the handshake and the function returns nonzero. Uses PID 1
+  # to also confirm a foreign-uid PID is not preventing the result.
+  ! is_party_alive 1 "$PARTY_TMP/no-such-sock"
+}