@Test
public void insertChild() throws Exception {
Node a = tree.find("a");
a.addChild(newNode("a1"));
a.addChild(newNode("a2"));
Assert.assertEquals(2, a.getNumberOfChildren());
Assert.assertEquals("{UNKNOWN,a,[a1,a2]}", a.toString());
a.insertChildAt(1, newNode("a11"));
Assert.assertEquals(3, a.getNumberOfChildren());