模拟可选参数时出现空指针异常

Question

我的代码是以下形式：

public String getDeliveryDestinations(final RequestContext requestContext {
    final Accessor accessor = requestContext.getAccessor().get();

    final GroupAccessor groupAccessor = accessor.getGroupAccessor();

    final String groupId = groupAccessor.getGroupId();


    if(groupId.equals("s1") return "Type1";
    else return "type 2";


}

为了测试这个，我写了以下内容：

@Test
public void getDestinationsDestinations_empty() throws Exception {


    Accessor accessor = mock(Accessor.class);
    GroupAccessor groupAccessor = mock(GroupAccessor.class);
    //*mockRequestContent is Mocked*
    when(mockRequestContext.getAccessor().get()).thenReturn(accessor);
    when(accessor.getGroupAccessor()).thenReturn(groupAccessor);
    when(groupAccessor.getGroupId()).thenReturn("s1");

    String destinationResult = provider.getDeliveryDestinations(mockRequestContext);
    assertEquals(destinationResult,"Type1");

}

我得到一个NPE，当（mockRequestContext.getAccessor（）。get（））。thenReturn（accessor）; 我不知道为什么！

任何线索都会非常有帮助:)

Answer 1

当getAccessor()需要返回一个可选项时，你可以这样做：

Accessor accessor = mock(Accessor.class);
GroupAccessor groupAccessor = mock(GroupAccessor.class);

Optional<Accessor> optAccessor = Optional.of(accesor)
when(mockRequestContext.getAccessor()).thenReturn(optAccessor)
when(accessor.getGroupAccessor()).thenReturn(groupAccessor);
when(groupAccessor.getGroupId()).thenReturn("s1");