@Test public void testHeight() { assertEquals(2, root.getHeight()); // depth of a assertEquals(1, root.getChildren().get(0).getHeight()); // depth of b assertEquals(0, root.getChildren().get(0).getChildren().get(0).getHeight()); // depth of c assertEquals(0, root.getChildren().get(0).getChildren().get(1).getHeight()); // depth of d assertEquals(0, root.getChildren().get(1).getHeight()); // depth of e }