public void getNextSiblingElement() {
// Pre-Assert
assertNull(e.getNextSiblingElement());
// Arrange
ButtonElement be0 = Document.get().createPushButtonElement();
ButtonElement be1 = Document.get().createPushButtonElement();
e.appendChild(be0);
e.appendChild(JsoUtils.newText("test1", Document.get()));
e.appendChild(be1);
e.appendChild(JsoUtils.newText("test2", Document.get()));
// Act & Assert
assertEquals(be1, be0.getNextSiblingElement());
assertNull(be1.getNextSiblingElement());
}