Add log to locate data null issue in IT

Signed-off-by: zane-neo <zaniu@amazon.com>

Author: zane-neo

plugin/src/test/java/org/opensearch/ml/rest/RestBedRockInferenceIT.java

@@ -302,10 +302,11 @@ private void validateOutput(String errorMsg, Map<String, Object> output, String
         List outputList = (List) output.get("output");
         assertEquals(errorMsg, 1, outputList.size());
         assertTrue(errorMsg, outputList.get(0) instanceof Map);
-        String typeErrorMsg = errorMsg
-            + " first element in the output list is type of: "
-            + ((Map<?, ?>) outputList.get(0)).get("data").getClass().getName();
-        assertTrue(typeErrorMsg, ((Map<?, ?>) outputList.get(0)).get("data") instanceof List);
+        assertNotNull(
+            "data in output list is null which is unexpected, output is: " + StringUtils.gson.toJson(output),
+            ((Map<?, ?>) outputList.get(0)).get("data")
+        );
+        assertTrue(errorMsg, ((Map<?, ?>) outputList.get(0)).get("data") instanceof List);
         assertEquals(errorMsg, ((Map<?, ?>) outputList.get(0)).get("data_type"), dataType);
     }
 

plugin/src/test/java/org/opensearch/ml/rest/RestCohereInferenceIT.java

@@ -88,10 +88,11 @@ private void validateOutput(String errorMsg, Map<String, Object> output, String
         List outputList = (List) output.get("output");
         assertEquals(errorMsg, 2, outputList.size());
         assertTrue(errorMsg, outputList.get(0) instanceof Map);
-        String typeErrorMsg = errorMsg
-            + " first element in the output list is type of: "
-            + ((Map<?, ?>) outputList.get(0)).get("data").getClass().getName();
-        assertTrue(typeErrorMsg, ((Map<?, ?>) outputList.get(0)).get("data") instanceof List);
+        assertNotNull(
+            "data in output list is null which is unexpected, output is: " + org.opensearch.ml.common.utils.StringUtils.gson.toJson(output),
+            ((Map<?, ?>) outputList.get(0)).get("data")
+        );
+        assertTrue(errorMsg, ((Map<?, ?>) outputList.get(0)).get("data") instanceof List);
         assertTrue(errorMsg, ((Map<?, ?>) outputList.get(0)).get("data_type").equals(dataType));
     }