Add a run-shell output test.

regress/run-shell-output.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+# 4476
+# run-shell should go to stdout if present without -t
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -Ltest"
+$TMUX kill-server 2>/dev/null
+
+TMP=$(mktemp)
+trap "rm -f $TMP" 0 1 15
+
+$TMUX -f/dev/null new -d "tmux run 'echo foo' >$TMP" || exit 1
+sleep 1 && [ "$(cat $TMP)" = "foo" ] || exit 1
+
+$TMUX -f/dev/null new -d "tmux run -t: 'echo foo' >$TMP; sleep 10" || exit 1
+sleep 1 && [ "$(cat $TMP)" = "" ] || exit 1
+[ "$($TMUX display -p '#{pane_mode}')" = "view-mode" ] || exit 1
+
+$TMUX kill-server 2>/dev/null
+
+exit 0