@Test
public void testExpand() {

  DefaultMutableTreeNode root = (DefaultMutableTreeNode)myModel.getRoot();
  checkTraverseOrder(root, " +Root +main - +A +main - +C - - +B +A - +main - - +C +main - - -");
  myModel.expand(findNodeOnPath(root, "Root", "B"));
  checkTraverseOrder(root, " +Root +main - +A +main - +C - - +B +A +C - +main - - +main - - +C +main - - -");
}