diff --git a/test/lib/library.sh b/test/lib/library.sh
index 1852c9b2..b4285f19 100644
--- a/test/lib/library.sh
+++ b/test/lib/library.sh
@@ -16,10 +16,13 @@ diff_env() {
 
 
 # Output array elements, sorted and separated by newline
+# Unset variable after outputting.
 # @param $1  Name of array variable to process
+# @param $2  -u (optional) Unset variable after echo
 echo_array() {
 	local IFS=$'\n'
-	eval echo \"\${$1[*]}\" | sort
+	eval printf "%s" \"\${$1[*]}\" | sort
+    unset -v $1
 }