EqOperator op = (EqOperator)functions.get(
new FunctionIdent(EqOperator.NAME, ImmutableList.<DataType>of(DataTypes.INTEGER, DataTypes.INTEGER)));
Function function = new Function(
op.info(), Arrays.<Symbol>asList(Literal.newLiteral(2), new InputColumn(1)));
FilterProjection projection = new FilterProjection(function);
projection.outputs(Arrays.<Symbol>asList(new InputColumn(0), new InputColumn(1)));
CollectingProjector collectingProjector = new CollectingProjector();
Projector projector = visitor.process(projection);
projector.registerUpstream(null);
projector.downstream(collectingProjector);