add test for cursor motion optimization

src/tests/Makefile.am

@@ -11,6 +11,7 @@ displaytests = \
 	e2e-failure.test \
 	emulation-80th-column.test \
 	emulation-back-tab.test \
+	emulation-cursor-motion.test \
 	emulation-multiline-scroll.test \
 	server-network-timeout.test \
 	server-signal-timeout.test \

src/tests/emulation-cursor-motion.test

@@ -0,0 +1,96 @@
+#!/bin/sh
+
+#
+# This test exercises a particular optimization involving small cursor
+# motions in Mosh.
+#
+fail()
+{
+    printf "$@" 2>&1
+    exit 99
+}
+
+
+
+PATH=$PATH:.:$srcdir
+# Top-level wrapper.
+if [ $# -eq 0 ]; then
+    e2e-test $0 baseline direct verify
+    exit
+fi
+
+# OK, we have arguments, we're one of the test hooks.
+if [ $# -ne 1 ]; then
+    fail "bad arguments %s\n" "$@"
+fi
+
+sleepf()
+{
+    (sleep .1 || sleep 1) > /dev/null 2>&1
+}
+
+seq()
+{
+    if [ $# -lt 1 -o $# -gt 3 ]; then
+	echo "bad args" >&2
+    fi
+    first=$1
+    incr=1
+    last=0
+    case $# in
+	3)
+	    incr=$2
+	    last=$3
+	    ;;
+	2)
+	    last=$2
+	    ;;
+	1)
+	    ;;
+    esac
+    while :; do
+	printf '%d\n' $first
+	first=$(expr $first + $incr)
+	if [ $first -gt $last ]; then
+	    break
+	fi
+    done
+}
+
+baseline()
+{
+    printf '\033[H\033[J'
+
+    while read x y text; do
+	printf '\033[%d;%dH%s' $y $x $text
+	sleepf
+    done <<EOF
+1 1 A
+10 1 B
+1 2 C
+1 4 D
+10 4 E
+1 7 F
+1 11 G
+10 11 H
+1 16 I
+2 16 J
+1 22 K
+60 23 L
+59 23 M
+57 23 N
+54 23 O
+50 23 P
+45 23 Q
+39 23 R
+32 23 S
+1 24 done
+EOF
+} 
+
+case $1 in
+    baseline|direct)
+	baseline;;
+    *)
+	fail "unknown test argument %s\n" $1;;
+esac