Add support for pretty printing XML fragments

Change-Id: I085e2e883cf445bfa406b0ae753df605b9929540
diff --git a/utils/misc/src/test/java/org/onlab/util/XmlStringTest.java b/utils/misc/src/test/java/org/onlab/util/XmlStringTest.java
index b09c44d..16954e5 100644
--- a/utils/misc/src/test/java/org/onlab/util/XmlStringTest.java
+++ b/utils/misc/src/test/java/org/onlab/util/XmlStringTest.java
@@ -41,4 +41,12 @@
         assertEquals(input, XmlString.prettifyXml(input).toString());
     }
 
+    @Test
+    public void fragments() {
+        String input = "<root/>   <a some='foo '/>";
+        String expected = "<root/>\n"
+                        + "<a some=\"foo \"/>\n";
+        assertEquals(expected, XmlString.prettifyXml(input).toString());
+    }
+
 }