Add more UT

protocol/src/test/java/com/amazon/opendistroforelasticsearch/sql/protocol/response/format/JdbcResponseFormatterTest.java

@@ -39,6 +39,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.gson.JsonParser;
 import java.util.Arrays;
+import org.elasticsearch.ElasticsearchException;
 import org.junit.jupiter.api.DisplayNameGeneration;
 import org.junit.jupiter.api.DisplayNameGenerator;
 import org.junit.jupiter.api.Test;
@@ -154,6 +155,25 @@ void format_server_error_response() {
     );
   }
 
+  @Test
+  void format_server_error_response_due_to_elasticsearch() {
+    assertJsonEquals(
+        "{\"error\":"
+            + "{\""
+            + "type\":\"ElasticsearchException\","
+            + "\"reason\":\"Error occurred in Elasticsearch engine: all shards failed\","
+            + "\"details\":\"ElasticsearchException[all shards failed]; "
+            + "nested: IllegalStateException[Execution error];; "
+            + "java.lang.IllegalStateException: Execution error\\n"
+            + "For more details, please send request for Json format to see the raw response "
+            + "from elasticsearch engine.\""
+            + "},"
+            + "\"status\":503}",
+        formatter.format(new ElasticsearchException("all shards failed",
+            new IllegalStateException("Execution error")))
+    );
+  }
+
   private static void assertJsonEquals(String expected, String actual) {
     assertEquals(
         JsonParser.parseString(expected),