Add some tests.

regress/cmd-invoke-readonly.sh

@@ -0,0 +1,56 @@
+#!/bin/sh
+
+# Read-only client enforcement.
+#
+# When the invoking client is read-only, cmd_invoke builds each command and
+# rejects it (without running it) unless the command entry is marked read-only.
+# A read-only client is created by attaching with -r; the nested-tmux pattern
+# from cmd-invoke-deferred.sh is used so a real read-only client presses a key.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+OUT="$TEST_TMUX -Ltest -f/dev/null"
+IN="$TEST_TMUX -Ltest2 -f/dev/null"
+
+$OUT kill-server 2>/dev/null
+$IN kill-server 2>/dev/null
+trap "$OUT kill-server 2>/dev/null; $IN kill-server 2>/dev/null" 0 1 15
+
+fail() { echo "[FAIL] $1" >&2; exit 1; }
+settle() { sleep 0.5; }
+
+# Inner session: a key bound to a non-read-only command.
+$IN new -d -x80 -y23 -nbase "sh -c 'exec sleep 1000'" || exit 1
+$IN set -g status on || exit 1
+$IN set -g status-keys emacs || exit 1
+$IN set -g window-size manual || exit 1
+$IN bind -n M-w new-window -dn ROTRY || exit 1
+
+# Outer session hosts the inner client, attached read-only with -r.
+$OUT new -d -x80 -y24 || exit 1
+$OUT set -g status off || exit 1
+$OUT set -g window-size manual || exit 1
+$OUT send-keys -l "$IN attach -r" || exit 1
+$OUT send-keys Enter || exit 1
+sleep 1
+
+[ "$($IN list-clients -F '#{client_readonly}')" = 1 ] || fail "client is not read-only"
+
+# Pressing the key runs new-window through the read-only client: it must be
+# rejected, leave no window, and report the error.
+$OUT send-keys M-w || exit 1
+settle
+$IN list-windows -F '#{window_name}' | grep -qx ROTRY && \
+	fail "read-only client was allowed to create a window"
+$OUT capture-pane -p | grep -qi 'read-only' || fail "no read-only error was shown"
+
+# Positive control: the same command with no client is not read-only and runs,
+# proving the command itself is valid and only the read-only client blocked it.
+$IN new-window -dn OKWIN || exit 1
+$IN list-windows -F '#{window_name}' | grep -qx OKWIN || fail "control new-window did not run"
+
+$OUT kill-server 2>/dev/null
+$IN kill-server 2>/dev/null
+exit 0