@Test
public void testEmptyInput() throws Exception{

	Row[] rows = new Row[]{
		Row.of(null, null),
		Row.of(1, null),
		Row.of(null, 1)
	};
	MemSourceBatchOp data = new MemSourceBatchOp(Arrays.asList(rows), new TableSchema(new String[]{"pred", "label"},
		new TypeInformation[]{Types.INT, Types.INT}));
	thrown.expect(Exception.class);
	EvalRegressionBatchOp op = new EvalRegressionBatchOp(new Params())
		.setLabelCol("label")
		.setPredictionCol("pred")
		.linkFrom(data);
	op.print();
}