Do not invoke gnuplot when there is nothing to plot

diff --git a/gw-tests/lib.sh b/gw-tests/lib.sh
index 4d6e2d7..467321d 100644 (file)
--- a/gw-tests/lib.sh
+++ b/gw-tests/lib.sh
@@ -44,6 +44,7 @@ _plot() {
     local testname=`basename $0 .sh`
 
     plot_cmds | sed -e "/set title/ s/[\"']\(.*\)[\"']/\"\1\\\\n($kvers)\"/" > plot.gp
+    if [[ ! -s plot.gp ]]; then return; fi
     if [ -z "$OPT_NO_X11" ]; then
        echo "set terminal x11 enhanced; $(< plot.gp)" | gnuplot -persist
     fi