Try to start writing test scripts.

regress/if-shell-error.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+# 883
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=../tmux
+TMUX="$TEST_TMUX -Ltest"
+$TMUX kill-server 2>/dev/null
+
+TMP=$(mktemp)
+trap "rm -f $TMP" 0 1 15
+
+cat <<EOF >$TMP
+if 'true' 'wibble wobble'
+EOF
+
+$TMUX -f$TMP new -d || exit 1
+sleep 1
+E=$($TMUX display -p '#{pane_in_mode}')
+$TMUX kill-server 2>/dev/null
+[ "$E" = "1" ] || exit 1
+
+exit 0