diff --git a/src/test/java/com/azure/cosmos/kafka/connect/source/CosmosDBSourceTaskTest.java b/src/test/java/com/azure/cosmos/kafka/connect/source/CosmosDBSourceTaskTest.java
index a46ed27d..fe6c05d6 100644
--- a/src/test/java/com/azure/cosmos/kafka/connect/source/CosmosDBSourceTaskTest.java
+++ b/src/test/java/com/azure/cosmos/kafka/connect/source/CosmosDBSourceTaskTest.java
@@ -98,7 +98,7 @@ public void setup() throws IllegalAccessException {
 
     @Test
     public void testHandleChanges() throws JsonProcessingException, IllegalAccessException, InterruptedException {
-        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
         List<JsonNode> changes = new ArrayList<>();
@@ -125,7 +125,7 @@ public void testHandleChanges() throws JsonProcessingException, IllegalAccessExc
 
     @Test
     public void testPoll() throws InterruptedException, JsonProcessingException, IllegalAccessException {
-        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
         List<JsonNode> changes = new ArrayList<>();
@@ -145,7 +145,7 @@ public void testPoll() throws InterruptedException, JsonProcessingException, Ill
     @Test
     public void testPoll_shouldFillMoreRecordsFalse() throws InterruptedException, JsonProcessingException, IllegalAccessException {
         // test when should fillMoreRecords false, then poll method will return immediately
-        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
 
@@ -169,7 +169,7 @@ public void testPoll_shouldFillMoreRecordsFalse() throws InterruptedException, J
 
     @Test
     public void testPollWithMessageKey() throws InterruptedException, JsonProcessingException {
-        String jsonString = "{\"id\":123,\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"id\":123,\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
         List<JsonNode> changes = new ArrayList<>();
@@ -204,7 +204,7 @@ public void testSourceRecordOffset() throws InterruptedException, JsonProcessing
 
     @Test
     public void testZeroBatchSize() throws InterruptedException, JsonProcessingException, IllegalAccessException {
-        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
         List<JsonNode> changes = new ArrayList<>();
@@ -223,7 +223,7 @@ public void testZeroBatchSize() throws InterruptedException, JsonProcessingExcep
 
     @Test
     public void testSmallBufferSize() throws InterruptedException, JsonProcessingException, IllegalAccessException {
-        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
         List<JsonNode> changes = new ArrayList<>();
@@ -243,7 +243,7 @@ public void testSmallBufferSize() throws InterruptedException, JsonProcessingExc
 
     @Test(expected=IllegalStateException.class)
     public void testEmptyAssignedContainerThrowsIllegalStateException() throws InterruptedException, JsonProcessingException, IllegalAccessException {
-        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\"}";
+        String jsonString = "{\"k1\":\"v1\",\"k2\":\"v2\", \"_lsn\":\"2\"}";
         ObjectMapper mapper = new ObjectMapper();
         JsonNode actualObj = mapper.readTree(jsonString);
         List<JsonNode> changes = new ArrayList<>();