diff --git a/utils/yangutils/src/test/resources/DerivedTypeStatement.yang b/utils/yangutils/src/test/resources/DerivedTypeStatement.yang
index 952b7d4..afbfd1d 100644
--- a/utils/yangutils/src/test/resources/DerivedTypeStatement.yang
+++ b/utils/yangutils/src/test/resources/DerivedTypeStatement.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     leaf invalid-interval {
         type P:hello;
     }
diff --git a/utils/yangutils/src/test/resources/DuplicateGroupingInList.yang b/utils/yangutils/src/test/resources/DuplicateGroupingInList.yang
index 2457cbe..a9d1b3b 100644
--- a/utils/yangutils/src/test/resources/DuplicateGroupingInList.yang
+++ b/utils/yangutils/src/test/resources/DuplicateGroupingInList.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     list valid {
         key address;
         grouping endpoint {
diff --git a/utils/yangutils/src/test/resources/DuplicateGroupingInModule.yang b/utils/yangutils/src/test/resources/DuplicateGroupingInModule.yang
index d18b166..ec01781 100644
--- a/utils/yangutils/src/test/resources/DuplicateGroupingInModule.yang
+++ b/utils/yangutils/src/test/resources/DuplicateGroupingInModule.yang
@@ -2,20 +2,23 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     grouping endpoint {
         leaf address {
-            type ip-address;
+            type P:ip-address;
         }
         leaf port {
-            type port-number;
+            type P:port-number;
         }
     }
     grouping endpoint {
         leaf address {
-            type ip-address;
+            type P:pip-address;
         }
         leaf port {
-            type port-number;
+            type P:port-number;
         }
     }
 }
diff --git a/utils/yangutils/src/test/resources/GroupingAttributes.yang b/utils/yangutils/src/test/resources/GroupingAttributes.yang
index 977adc5..f04641f 100644
--- a/utils/yangutils/src/test/resources/GroupingAttributes.yang
+++ b/utils/yangutils/src/test/resources/GroupingAttributes.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     list valid {
         key address;
         leaf address {
diff --git a/utils/yangutils/src/test/resources/GroupingInContainer.yang b/utils/yangutils/src/test/resources/GroupingInContainer.yang
index 7c51913..dfa8259 100644
--- a/utils/yangutils/src/test/resources/GroupingInContainer.yang
+++ b/utils/yangutils/src/test/resources/GroupingInContainer.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     container valid {
         grouping endpoint {
             leaf address {
diff --git a/utils/yangutils/src/test/resources/GroupingInList.yang b/utils/yangutils/src/test/resources/GroupingInList.yang
index a8fad09..c5966fc 100644
--- a/utils/yangutils/src/test/resources/GroupingInList.yang
+++ b/utils/yangutils/src/test/resources/GroupingInList.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     list valid {
         key address;
         leaf address {
diff --git a/utils/yangutils/src/test/resources/GroupingInModule.yang b/utils/yangutils/src/test/resources/GroupingInModule.yang
index 7d513a4..77fef1f 100644
--- a/utils/yangutils/src/test/resources/GroupingInModule.yang
+++ b/utils/yangutils/src/test/resources/GroupingInModule.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     grouping endpoint {
         leaf address {
             type P:ip-address;
diff --git a/utils/yangutils/src/test/resources/SelfFileLinkingWithTypdefHierarchicalRefUnresolved.yang b/utils/yangutils/src/test/resources/SelfFileLinkingWithTypdefHierarchicalRefUnresolved.yang
index 35c28b6..a3e4379 100644
--- a/utils/yangutils/src/test/resources/SelfFileLinkingWithTypdefHierarchicalRefUnresolved.yang
+++ b/utils/yangutils/src/test/resources/SelfFileLinkingWithTypdefHierarchicalRefUnresolved.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     typedef Percentage {
     type P:Per;
     }
diff --git a/utils/yangutils/src/test/resources/SelfFileLinkingWithTypeWithSelfAndExternalPrefixMix.yang b/utils/yangutils/src/test/resources/SelfFileLinkingWithTypeWithSelfAndExternalPrefixMix.yang
index 038c7de..d5f346e 100644
--- a/utils/yangutils/src/test/resources/SelfFileLinkingWithTypeWithSelfAndExternalPrefixMix.yang
+++ b/utils/yangutils/src/test/resources/SelfFileLinkingWithTypeWithSelfAndExternalPrefixMix.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     typedef Percentage {
     type int32;
     }
diff --git a/utils/yangutils/src/test/resources/UsesInList.yang b/utils/yangutils/src/test/resources/UsesInList.yang
index c4fd47d..b79e7b1 100644
--- a/utils/yangutils/src/test/resources/UsesInList.yang
+++ b/utils/yangutils/src/test/resources/UsesInList.yang
@@ -2,6 +2,9 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
+    import ietf-yang-types {
+             prefix "P";
+         }
     list valid {
         key address;
         leaf address {
diff --git a/utils/yangutils/src/test/resources/ValidAugmentStatement.yang b/utils/yangutils/src/test/resources/ValidAugmentStatement.yang
index 59ebe67..6175c35 100644
--- a/utils/yangutils/src/test/resources/ValidAugmentStatement.yang
+++ b/utils/yangutils/src/test/resources/ValidAugmentStatement.yang
@@ -6,6 +6,9 @@
     import interface-module {
         prefix "if";
     }
+    import ietf-yang-types {
+             prefix "P";
+         }
     augment "/if:interfaces/if:ifEntry" {
         when "if:ifType='ds0'";
         leaf ds0ChannelNumber {
diff --git a/utils/yangutils/src/test/resources/ValidNotificationStatement.yang b/utils/yangutils/src/test/resources/ValidNotificationStatement.yang
index d588bb9..072df23 100644
--- a/utils/yangutils/src/test/resources/ValidNotificationStatement.yang
+++ b/utils/yangutils/src/test/resources/ValidNotificationStatement.yang
@@ -2,6 +2,9 @@
     namespace "http://example.net/rock";
     prefix "rock";
 
+    import ietf-yang-types {
+             prefix "P";
+         }
     notification link-failure {
         description "A link failure has been detected";
         status deprecated;