### Question:
DecisionTree extends DelegateTree<DecisionTreeNode, DecisionTreeEdge> { public String getLabel(Category category) { List<LeafNode> leafs = findLeafNodes(category); List<String> labels = new ArrayList<String>(); for (LeafNode leaf : leafs) { labels.add(getLabel(leaf)); } Collections.sort(labels); if(labels.size() < 2) { return StringUtils.join(labels, ") OR ("); } else { return "(" + StringUtils.join(labels, ") OR (") + ")"; } } DecisionTree(final DecisionTreeNode rootNode); ObservableGraph<DecisionTreeNode, DecisionTreeEdge> getObservableGraph(); LeafNode decide(final Object obj); DecisionTreeNode getEdgeTarget(final DecisionTreeEdge e); DecisionTreeNode getEdgeSource(final DecisionTreeEdge e); DecisionTreeEdge findMatchingEdge(final DecisionTreeNode parent, final Object value); void replaceChild(final DecisionTreeEdge edge, final DecisionTreeNode newChild); boolean equivalent(DecisionTree obj); String getLabel(Category category);  }### Answer:
@Test public void testToString() { TreatmentCategorization catz1 = ExampleData.buildCategorizationFixedDose(ExampleData.buildDrugFluoxetine()); assertEquals("Class Fixed", catz1.getDecisionTree().getLabel(catz1.getCategories().get(0))); TreatmentCategorization catz2 = ExampleData.buildCategorizationUpto20mg(ExampleData.buildDrugFluoxetine()); assertEquals("(Class Fixed AND Quantity 0.00 ≤ x ≤ 20.00) OR (Class Flexible AND Max Dose 0.00 ≤ x ≤ 20.00)", catz2.getDecisionTree().getLabel(catz2.getCategories().get(0))); }