### Question:
ExpandableList extends Node implements List<INode> { @Override public int indexOf(Object o) { return list.indexOf(o); } ExpandableList();  ExpandableList(Collection<? extends INode> children); void insertAll(Collection<? extends INode> children); void insertAll(int index, Collection<? extends INode> children); @Override void setExpanded(boolean expanded); @Override boolean isExpanded(); int expand(INode node); int collapse(INode node); void collapseAll(); void expandAll(); int absoluteSize(); int getChildCount(); INode getChild(int index); void invalidate(); void setExpandedDeep(boolean expanded); @Deprecated @Override void setParent(INode parent); @Override INode getParent(); @Override void onInserted(INode child); @Override void onChanged(INode node); @Override void onDeleted(INode fromParent, INode child); @Override String toString(); @Override int size(); @Override INode get(int index); @Override boolean isEmpty(); @Override boolean contains(Object o); @Override INode[] toArray(); @Override E[] toArray(E[] ts); @Override boolean containsAll(Collection<?> collection); @Override int indexOf(Object o); @Override int indexOf(INode child); @Override int lastIndexOf(Object o); @Override Iterator<INode> iterator(); @Override ListIterator<INode> listIterator(); @Override ListIterator<INode> listIterator(int index); @Override List<INode> subList(int from, int to); @Deprecated @Override boolean add(INode node); @Deprecated @Override void add(int index, INode node); @Deprecated @Override boolean remove(Object o); @Deprecated @Override boolean addAll(Collection<? extends INode> collection); @Deprecated @Override boolean addAll(int index, Collection<? extends INode> collection); @Deprecated @Override boolean removeAll(Collection<?> collection); @Deprecated @Override boolean retainAll(Collection<?> collection); @Deprecated @Override INode set(int index, INode node); @Deprecated @Override INode remove(int i);  }### Answer:
@SuppressWarnings("SuspiciousMethodCalls") @Test public void indexOf() { Node target = new Node(); INode node = new NodeBuilder(false).add(target).build(); ExpandableList list = new ListBuilder() .add(new Node()) .add(node) .add(new Node()) .build(); assertEquals(-1, list.indexOf(target)); assertEquals(-1, list.indexOf((Object) target)); node.setExpanded(true); assertEquals(2, list.indexOf(target)); assertEquals(2, list.indexOf((Object) target)); }