[ONOS-5135]config issue + augment flag

Change-Id: I56112023cfe64eecb16796a29ad0137952fbe49a
diff --git a/plugin/src/test/java/org/onosproject/yangutils/parser/impl/listeners/MustListenerTest.java b/plugin/src/test/java/org/onosproject/yangutils/parser/impl/listeners/MustListenerTest.java
index 2649d4d..ea6708b 100644
--- a/plugin/src/test/java/org/onosproject/yangutils/parser/impl/listeners/MustListenerTest.java
+++ b/plugin/src/test/java/org/onosproject/yangutils/parser/impl/listeners/MustListenerTest.java
@@ -72,4 +72,13 @@
 
         assertThat(leafInfo.getListOfMust().iterator().next().getConstraint(), is("ifType != 'ethernet'"));
     }
+
+    /**
+     * Checks whether there is no parser exception when must statement is sub-statement of
+     * unsupported yang construct.
+     */
+    @Test
+    public void processUnsupportedSubStatementMust() throws IOException, ParserException {
+        YangNode node = manager.getDataModel("src/test/resources/UnsupportedYangConstructSubStatementMust.yang");
+    }
 }
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diff --git a/plugin/src/test/resources/UnsupportedYangConstructSubStatementMust.yang b/plugin/src/test/resources/UnsupportedYangConstructSubStatementMust.yang
new file mode 100644
index 0000000..1529cfd
--- /dev/null
+++ b/plugin/src/test/resources/UnsupportedYangConstructSubStatementMust.yang
@@ -0,0 +1,17 @@
+module Test {
+    yang-version 1;
+    namespace "http://huawei.com";
+    prefix Ant;
+    list link-scope-lsa {
+        key "lsa-id adv-router";
+        description "List of OSPF link scope LSAs";
+        uses lsa {
+            refine "version/ospfv2/ospfv2" {
+                must "../../../../../../../../../../../"
+                   + "rt:type = 'ospf:ospfv2'" {
+                  description "OSPFv2 LSA.";
+                }
+            }
+        }
+    }
+}
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