@Test public void createCategoryWithNoFields() { PropertyEditorWidget propertyEditorWidget = GWT.create(PropertyEditorWidget.class); Accordion propertyMenu = GWT.create(Accordion.class); PropertyEditorCategory category = new PropertyEditorCategory("1"); PropertyEditorHelper.createCategory(propertyEditorWidget, propertyMenu, category, ""); verify(propertyMenu, never()).add(any(Widget.class)); }