@Test
public void project_schema() {

  PhysicalPlan project = project(inputPlan,
      DSL.named("response", DSL.ref("response", INTEGER)),
      DSL.named("action", DSL.ref("action", STRING)));
  assertThat(project.schema().getColumns(), contains(
      new ExecutionEngine.Schema.Column("response", null, INTEGER),
      new ExecutionEngine.Schema.Column("action", null, STRING)
  ));
}