private void triggerEmptyResultSetForAllDataCenters(List<String> datacenters) {
      for (String datacenter : datacenters) {
        try {
          DataSource dataSource = dataSources.get(datacenter);
          reset(dataSource);
          PreparedStatement statement = mock(PreparedStatement.class);
          ResultSet resultSet = mock(ResultSet.class);
          when(resultSet.next()).thenReturn(false);
          when(statement.executeQuery()).thenReturn(resultSet);
          Connection connection = mock(Connection.class);
          when(connection.prepareStatement(any())).thenReturn(statement);
          when(dataSource.getConnection()).thenReturn(connection);
        } catch (SQLException e) {
          throw new RuntimeException(e);
        }
      }
    }
@param callable an async call, where the {@link Future} is expected to be completed with an exception.
@param errorCode the expected {@link RestServiceErrorCode}.
ambry-named-mysql/src/test/java/com/github/ambry/named/MySqlNamedBlobDbTest.java