public void FindVisualDescendantTest() { UITester.Dispatcher.Invoke(() => { var dummy = WPFHelper.FindVisualDescendant <Button>(null); Assert.IsNull(dummy); var treeViewItem = testTreeView.FindVisualDescendant <TreeViewItem>(); Assert.IsNotNull(treeViewItem); Assert.IsInstanceOfType(treeViewItem, typeof(TreeViewItem)); }); }