### Question:
AgnosticTreeView implements TreeView { @Override public void initToolTips(ToolTipProperties properties) { polygonPanel.addMouseMotionListener(new ToolTipListener(properties, polygonPanel, cascade)); } AgnosticTreeView(PolygonPanel polygonPanel); @Override void addNodeInteractionListener(NodeInteractionListener listener); @Override void colorNode(String nodeId, RGBColor color); @Override void addCascadeLoadedListener(CascadeLoadedListener listener); @Override void setCanvasBackground(RGBColor color); @Override void loadCascade(Cascade newCascade, boolean resetView); @Override void addSpecialControl(String nodeId, SpecialControl specialControl); @Override void initNodeNames(); @Override void initToolTips(ToolTipProperties properties); @Override void loadNodeNamesFrom(NodePresentationProperties nodePresentationProperties); @Override void clear(); @Override void registerSpecialType(Class contentClass, ContentFactory factory);  }### Answer:
@Test public void registersToolTipListener() { ToolTipProperties properties = mock(ToolTipProperties.class); treeView.initToolTips(properties); verify(panel).addMouseMotionListener(isA(ToolTipListener.class)); }