### Question:
BackPath { public BackPath<E, N> getParent() { return parent; } BackPath(BackPath<E, N> parent, N node); BackPath<E, N> getParent(); N getNode(); List<N> toPath();  }### Answer:
@Test public void testGetNullParent() throws Exception { final BackPath<String, BinaryTreeNode<String>> backPath = new BackPath<>(null, node); assertNull(backPath.getParent()); }
@Test public void testGetParent() throws Exception { BackPath<String, BinaryTreeNode<String>> parentBackPath = new BackPath<>(null, parent); final BackPath<String, BinaryTreeNode<String>> backPath = new BackPath<>(parentBackPath, node); assertEquals(parentBackPath, backPath.getParent()); }