### Question:
GTreeNode extends CoreGTreeNode implements Comparable<GTreeNode> { public boolean isAncestor(GTreeNode node) { GTreeNode nodeParent = node.getParent(); while (nodeParent != null) { if (nodeParent.equals(this)) { return true; } nodeParent = nodeParent.getParent(); } return false; }  String getDisplayText(); abstract String getName(); abstract Icon getIcon(boolean expanded); abstract String getToolTip(); abstract boolean isLeaf(); @Override int compareTo(GTreeNode node); void addNode(GTreeNode node); void addNodes(List<GTreeNode> nodes); void addNode(int index, GTreeNode node); List<GTreeNode> getChildren(); int getChildCount(); GTreeNode getChild(String name); GTreeNode getChild(int index); int getNodeCount(); int getLeafCount(); int getIndexInParent(); int getIndexOfChild(GTreeNode node); TreePath getTreePath(); void removeAll(); void removeNode(GTreeNode node); void setChildren(List<GTreeNode> childList); boolean isAncestor(GTreeNode node); void valueChanged(Object newValue); boolean isEditable(); GTreeNode getRoot(); boolean isRoot(); GTreeNode filter(GTreeFilter filter, TaskMonitor monitor); int loadAll(TaskMonitor monitor); @Override int hashCode(); @Override boolean equals(Object obj); Stream<GTreeNode> stream(boolean depthFirst); Iterator<GTreeNode> iterator(boolean depthFirst); @Override String toString(); void fireNodeStructureChanged(GTreeNode node); void fireNodeChanged(GTreeNode parentNode, GTreeNode node); void expand(); void collapse(); boolean isExpanded();  }### Answer:
@Test public void isAncestor() { assertTrue(root.isAncestor(node0_0)); assertFalse(node0_0.isAncestor(root)); }