@Test public void testOpen() throws Exception { excelSink.open(); // // verify that inputOperator called open() method Mockito.verify(inputOperator).open(); // // assert that the tuple stream sink removes the _ID and PAYLOAD attribute Assert.assertEquals(new Schema(new Attribute("content", AttributeType.TEXT)), excelSink.getOutputSchema()); excelSink.close(); Files.deleteIfExists(excelSink.getFilePath()); }