@Override
  protected void setUp() {
    EditorTestingUtil.setupTestEnvironment();

    ContentDocElement.register(ROOT_HANDLER_REGISTRY, ContentDocElement.DEFAULT_TAGNAME);
    Paragraph.register(ROOT_HANDLER_REGISTRY);
    LineRendering.registerLines(ROOT_HANDLER_REGISTRY);

    LineRendering.registerParagraphRenderer(
        Editor.ROOT_HANDLER_REGISTRY, new Renderer(renderer, renumberer, runner));

    renumberer.updateHtmlEvenWhenNullImplNodelet = true;

    DocInitializationBuilder builder = new DocInitializationBuilder();
    builder.elementStart("body", Attributes.EMPTY_MAP);
    for (int i = 0; i < SIZE; i++) {
      builder.elementStart("line", Attributes.EMPTY_MAP).elementEnd();
    }
    builder.elementEnd();

    content1 = new ContentDocument(ConversationSchemas.BLIP_SCHEMA_CONSTRAINTS);
    content1.setRegistries(Editor.ROOT_REGISTRIES);
    content1.consume(builder.build());
    doc1 = content1.getMutableDoc();

    content2 = new ContentDocument(ConversationSchemas.BLIP_SCHEMA_CONSTRAINTS);
    content2.setRegistries(Editor.ROOT_REGISTRIES);
    content2.consume(builder.build());
    doc2 = content2.getMutableDoc();

    doc = doc1;

    runTask();
  }