diff --git a/CHANGELOG.md b/CHANGELOG.md
index e82376a6d1..d0468ecf3a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Features
 ### Enhancements
 ### Bug Fixes
+* Fixing KNNCodecServiceTests as reported in the gh issue:[#1593] [#1601](https://github.com/opensearch-project/k-NN/pull/1601) 
 ### Infrastructure
 ### Documentation
 ### Maintenance
diff --git a/src/test/java/org/opensearch/knn/index/codec/KNNCodecServiceTests.java b/src/test/java/org/opensearch/knn/index/codec/KNNCodecServiceTests.java
index 233b9adf77..dfe4e7f22a 100644
--- a/src/test/java/org/opensearch/knn/index/codec/KNNCodecServiceTests.java
+++ b/src/test/java/org/opensearch/knn/index/codec/KNNCodecServiceTests.java
@@ -36,6 +36,7 @@ public void setUp() throws Exception {
         super.setUp();
         IndexMetadata indexMetadata = mock(IndexMetadata.class);
         when(indexMetadata.getIndex()).thenReturn(new Index(TEST_INDEX, INDEX_UUID.toString()));
+        when(indexMetadata.getCustomData(IndexMetadata.REMOTE_STORE_CUSTOM_KEY)).thenReturn(null);
         when(indexMetadata.getSettings()).thenReturn(Settings.EMPTY);
         Settings settings = Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, Integer.toString(NUM_OF_SHARDS)).build();
         indexSettings = new IndexSettings(indexMetadata, settings);