SNOW-958531 add retries for test_null_connection (#1791)

test/integ/test_cursor.py

@@ -1613,13 +1613,21 @@ def test_fetch_batches_with_sessions(conn_cnx):
 
 @pytest.mark.skipolddriver
 def test_null_connection(conn_cnx):
+    retries = 15
     with conn_cnx() as con:
         with con.cursor() as cur:
             cur.execute_async(
                 "select seq4() as c from table(generator(rowcount=>50000))"
             )
             con.rest.delete_session()
             status = con.get_query_status(cur.sfqid)
+            for _ in range(retries):
+                if status not in (QueryStatus.RUNNING,):
+                    break
+                time.sleep(1)
+                status = con.get_query_status(cur.sfqid)
+            else:
+                pytest.fail(f"query is still running after {retries} retries")
             assert status == QueryStatus.FAILED_WITH_ERROR
             assert con.is_an_error(status)