Add dmenu test.

Makefile.am

@@ -90,3 +90,4 @@ test: rofi
 	make -C test/ test
 	./test/run_errormsg_test.sh
 	./test/run_switchdialog_test.sh
+	./test/run_dmenu_test.sh

test/run_dmenu_test.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+# Create fake X
+Xvfb :202 &
+XPID=$!
+
+# wait till it is up, run rofi with error message
+sleep 1;
+echo -e -n "aap\nnoot\nmies" | ./rofi -dmenu -display :202 > output.txt & 
+RPID=$!
+
+# send enter.
+sleep 5;
+DISPLAY=:202 xdotool key 'Down' 
+sleep 0.4
+DISPLAY=:202 xdotool key 'Down'
+sleep 0.4
+DISPLAY=:202 xdotool key Return
+
+#  Get result, kill xvfb
+wait ${RPID}
+RETV=$?
+kill ${XPID}
+
+sleep 1
+
+if [ `cat output.txt` != 'aap' ]
+then
+    exit 1
+fi
+exit ${RETV}