### Question:
WXScroller extends WXVContainer<ViewGroup> implements WXScrollViewListener,Scrollable { @Override public void addChild(WXComponent child, int index) { mChildrenLayoutOffset += child.getLayoutTopOffsetForSibling(); if (child instanceof WXBaseRefresh) { if (!checkRefreshOrLoading(child)) { mRefreshs.add(child); } } super.addChild(child,index); } @Deprecated  WXScroller(WXSDKInstance instance, WXDomObject dom, WXVContainer parent, String instanceId, boolean isLazy);  WXScroller(WXSDKInstance instance, WXDomObject node,
                    WXVContainer parent); @Override ViewGroup getRealView(); @Override void createViewImpl(); ViewGroup getInnerView(); @Override void addEvent(String type); Map<String, Object> getScrollEvent(int x, int y); @Override void addSubView(View child, int index); @Override void addChild(WXComponent child, int index); @Override void remove(WXComponent child,boolean destory); @Override void destroy(); @Override int getScrollY(); @Override int getScrollX(); @Override int getOrientation(); Map<String, Map<String, WXComponent>> getStickMap(); @WXComponentProp(name = Constants.Name.SHOW_SCROLLBAR) void setShowScrollbar(boolean show); @WXComponentProp(name = Constants.Name.SCROLLABLE) void setScrollable(boolean scrollable); @WXComponentProp(name = Constants.Name.OFFSET_ACCURACY) void setOffsetAccuracy(int accuracy); @Override boolean isScrollable(); @Override void bindStickStyle(WXComponent component); @Override void unbindStickStyle(WXComponent component); @Override void bindAppearEvent(WXComponent component); @Override void bindDisappearEvent(WXComponent component); @Override void unbindAppearEvent(WXComponent component); @Override void unbindDisappearEvent(WXComponent component); @Override void scrollTo(WXComponent component, Map<String, Object> options); void scrollBy(final int x, final int y); void scrollBy(final int x, final int y, final boolean smooth); @Override void onScrollChanged(WXScrollView scrollView, int x, int y,
                              int oldx, int oldy); @Override void onScrollToBottom(WXScrollView scrollView, int x, int y); @Override void onScrollStopped(WXScrollView scrollView, int x, int y); @Override void onScroll(WXScrollView scrollView, int x, int y); @JSMethod void resetLoadmore(); ScrollStartEndHelper getScrollStartEndHelper(); @WXComponentProp(name = "pagingEnabled") void setPagingEnable(boolean pagingEnable); static final String DIRECTION; }### Answer:
@Test public void testAddChild() throws Exception{ WXDiv div = WXDivTest.create(component); component.addChild(div); ComponentTest.create(div); }