testGetNextSibling() {
    setUpDomTree();

    assertEquals(
        'Child 1 should have Child 2', childNode2,
        editorNode.getNextSibling(childNode1));
    assertEquals(
        'Child 2 should have child 3', childNode3,
        editorNode.getNextSibling(childNode2));
    assertNull(
        'Child 3 has no next sibling', editorNode.getNextSibling(childNode3));
    assertNotEquals(
        'Should not skip ws and nbsp nodes', gChildTextNode1,
        editorNode.getNextSibling(gChildMixedNode1));
    assertNotEquals(
        'Should not skip nbsp node', gChildTextNode1,
        editorNode.getNextSibling(gChildWsNode1));
    assertEquals(
        'Should have sibling', gChildTextNode1,
        editorNode.getNextSibling(gChildNbspNode1));
    assertNull(
        'Should have no next sibling',
        editorNode.getNextSibling(gChildTextNode1));
    assertNull(
        'Only has ws sibling', editorNode.getNextSibling(gChildWsNode2a));
    assertNull(
        'Has no next sibling', editorNode.getNextSibling(gChildWsNode2b));
    assertEquals(
        'Should skip ws node', gChildTextNode3b,
        editorNode.getNextSibling(gChildTextNode3a));

    tearDownDomTree();
  }
Creates a DOM tree and tests that getNextSibling properly ignores
igrnorable nodes when determining the next sibling