### Question:
TreatmentCategorizationWizardPresentation extends PresentationModel<TreatmentCategorization> { public ObservableList<Category> getCategories() { return getBean().getCategories(); } TreatmentCategorizationWizardPresentation(final TreatmentCategorization bean, final Domain domain); boolean isLeafNodeReachable(DecisionTreeNode node, Category category); ValueModel getDrug(); ValueModel getName(); ObservableList<Category> getCategories(); DoseUnit getDoseUnit(); DoseUnitPresentation getDoseUnitPresentation(); TreatmentCategorization commit(); ObservableList<DecisionTreeEdge> getOutEdges(final DecisionTreeNode node); String getCategory(final AbstractDose dose); DecisionTreeEdge findTypeEdge(final Class<?> type); ValueModel getModelForEdge(final DecisionTreeEdge edge); ValueModel getModelForUnknownDose(); ValueModel getModelForKnownDose(); ValueModel getModelForFixedDose(); ValueModel getModelForFlexibleDose(); ValueModel getConsiderDoseType(); ValueModel getIgnoreDoseType(); ValueModel getConsiderFixed(); ValueModel getConsiderFlexibleLowerFirst(); ValueModel getConsiderFlexibleUpperFirst(); ObservableList<DecisionTreeEdge> getFlexibleLowerRanges(); ObservableList<DecisionTreeEdge> getFlexibleUpperRanges(); ChoiceNode getFlexibleLowerRangeNode(); ChoiceNode getFlexibleUpperRangeNode(); ChoiceNode getFixedRangeNode(); ValueModel getCategoryUsed(Category category); ObservableList<DecisionTreeNode> getOptionsForEdge(final DecisionTreeEdge edge); ObservableList<DecisionTreeNode> getOptionsForKnownDose(); ObservableList<DecisionTreeNode> getOptionsForUnknownDose(); ObservableList<DecisionTreeNode> getOptionsForFixedDose(); ObservableList<DecisionTreeNode> getOptionsForFlexibleDose(); void transformTree(); Pair<RangeEdge> splitRange(final RangeEdge range, final double value, final boolean lowerRangeOpen); static LeafNode findLeafNode(final Collection<DecisionTreeNode> haystack, final Category needle); RangeEdge addDefaultRangeEdge(ChoiceNode node); ValueModel getNameAvailableModel();  }### Answer:
@Test public void testMessWithCategories() { final Category catNode1 = new Category(d_bean, "foo"); final Category catNode2 = new Category(d_bean, "bar"); d_pm.getCategories().add(catNode1); d_pm.getCategories().add(catNode2); assertEquals(Arrays.asList(catNode1, catNode2), d_pm.getCategories()); d_pm.getCategories().remove(catNode1); assertEquals(Arrays.asList(catNode2), d_pm.getCategories()); }