[ONOS-6783] Data type handling in Data Node

Change-Id: I5d27e169f95e2a5af89a866c1d34281201c73c56
diff --git a/serializers/xml/src/test/resources/food.yang b/serializers/xml/src/test/resources/food.yang
index 4c87fa0..861ef3a 100644
--- a/serializers/xml/src/test/resources/food.yang
+++ b/serializers/xml/src/test/resources/food.yang
@@ -44,7 +44,7 @@
            }
        }
        leaf p1 {
-           type string;
+           type empty;
        }
        leaf-list p2 {
            type string;
diff --git a/serializers/xml/src/test/resources/testContainer.xml b/serializers/xml/src/test/resources/testContainer.xml
index ee679b8..98d44f8 100644
--- a/serializers/xml/src/test/resources/testContainer.xml
+++ b/serializers/xml/src/test/resources/testContainer.xml
@@ -1,5 +1,5 @@
 <food xmlns="yrt:food">
-<p1>p1_value</p1>
+<p1/>
 <p2>p2_value</p2>
 <p2>p2_value1</p2>
 </food>