@Test
public void
a_node_with_two_children_generates_two_plans(){

   DFSTree tree = DFSTreeBuilder.aTreeBuilder().withLabel(0).withChild(DFSTreeBuilder.aTreeBuilder().withLabel(1)).
                                                            withChild(DFSTreeBuilder.aTreeBuilder().withLabel(2)).build();
   assertThat(tree.generateCombinations()).isEqualTo(Lists.newArrayList("0,1,2","0,2,1"));
}