如何在Spock测试框架中模拟服务类注入?

我有一个Java服务,它很少有Guice注入的东西。

public class RecoveryServiceImpl implements RecoveryService {
    @Inject
    public RecoveryServiceImpl(SessionInstanceCache sessionInstanceCache, AttendeeCache attendeeCache, MessagingStreamConfiguration messagingConfig) {
        this.sessionInstanceCache = sessionInstanceCache;
        this.attendeeCache = attendeeCache;
        this.messagingConfig = messagingConfig;
    }

    @Override
    public SessionInstanceData recoverSessionInstance(SessionInstanceDto sessionInstance) {
        SessionInstanceData sessionInstanceData = SessionInstanceHelper.recoverSessionInstance(sessionInstance);

        if (sessionInstanceData.getDeepstreamServerKey() == null) {
            String dsKey = SessionInstanceHelper.pickRandomDeepstreamServerKey(
                sessionInstanceData, messagingConfig);

这样做:

public static String pickRandomDeepstreamServerKey(
        SessionInstanceData sessionInstanceData, MessagingStreamConfiguration dsConfig) {
    // NPE occurs here
    List<String> dsKeys = new ArrayList(dsConfig.getBaseUrls().keySet()); 

这是用斯波克测试的。 我添加了 messagingConfig 现在我正努力让它在斯波克测试中被嘲笑:

class RecoveryServiceImplTest extends Specification {

...
    MessagingStreamConfiguration msgConfig = Mock(MessagingStreamConfiguration);
    RecoveryService recoveryService = new RecoveryServiceImpl(sessionInstanceCache, attendeeCache, msgConfig);

    def "Recover session instance"() {
        ...
        def dsMap = new HashMap<String, URL>();
        dsMap.put("ds1", new URL("http://ilovemocking.com/"));

        when:
        msgConfig.getBaseUrls() >> dsMap;
        //msgConfig.getBaseUrls().keySet() >> new HashSet(){{add("ds1")}};
        recoveryService.recoverSessionInstance(sessionInstanceDto)

打电话给 recoverSessionInstance() ,我得到一个 NPE 因为 getBaseUrls() 返回空值。

我尝试了另一种方法,实例化 msgConfig 作为普通对象(也称为“stubing”),但结果相同。

我该怎么让斯波克假装 dsMap 而不是 null 是吗?