@Test
public void shouldPerformSimpleGroupBy() {

	final SopremoTestPlan sopremoPlan = new SopremoTestPlan(1, 1);
	final Grouping aggregation = new Grouping().withResultProjection(
		createFunctionCall(CoreFunctions.COUNT, new InputSelection(0)));
	aggregation.setInputs(sopremoPlan.getInputOperator(0));
	sopremoPlan.getOutputOperator(0).setInputs(aggregation);
	sopremoPlan.getInput(0).
		addObject("id", 1, "dept", 1, "income", 12000).
		addObject("id", 2, "dept", 1, "income", 13000).
		addObject("id", 3, "dept", 2, "income", 15000).
		addObject("id", 4, "dept", 1, "income", 10000).
		addObject("id", 5, "dept", 3, "income", 8000).
		addObject("id", 6, "dept", 2, "income", 5000).
		addObject("id", 7, "dept", 1, "income", 24000);
	sopremoPlan.getExpectedOutput(0).
		addValue(7);
	sopremoPlan.trace();
	sopremoPlan.run();
}