### Question:
RrdtoolDataSource implements JRDataSource { public boolean next() throws JRException { m_currentRow++; return m_data == null || m_data.getData() == null ? false : m_currentRow < m_data.getData().getRowCount(); } RrdtoolDataSource(Xport data); Object getFieldValue(JRField field); boolean next();  }### Answer:
@Test public void testEmptyData() throws Exception { RrdtoolDataSource ds = new RrdtoolDataSource(null); Assert.assertFalse(ds.next()); }