Mock base class method with Easymock

Question

I have the following test code:

    herder = PowerMock.createPartialMock(DistributedHerder.class, new String[]{"backoff", "updateDeletedConnectorStatus"},
            new DistributedConfig(HERDER_CONFIG), worker, WORKER_ID, statusBackingStore, configBackingStore, member, MEMBER_URL, time);

    configUpdateListener = herder.new ConfigUpdateListener();
    rebalanceListener = herder.new RebalanceListener();
    plugins = PowerMock.createMock(Plugins.class);
    EasyMock.expect(worker.getPlugins()).andReturn(plugins);
    EasyMock.expect(herder.connectorType(CONN1)).andReturn(ConnectorType.SOURCE).anyTimes();

where connectorType() method is defined in AbstractHerder, base class of DistributedHerder. Since the herder is created off of DistributedHerder, easy mock doesn't find mock for AbstractHerder class, leading to NPE:

org.apache.kafka.connect.runtime.distributed.DistributedHerderTest > testInconsistentConfigs FAILED
  java.lang.NullPointerException
    at org.apache.kafka.connect.runtime.AbstractHerder.getConnector(AbstractHerder.java:342)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerder$$EnhancerByCGLIB$$af0dd240.CGLIB$getConnector$39(<generated>)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerder$$EnhancerByCGLIB$$af0dd240$$FastClassByCGLIB$$8c31132d.invoke(<generated>)
    at org.easymock.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
    at org.easymock.internal.ClassProxyFactory$MockMethodInterceptor.intercept(ClassProxyFactory.java:92)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerder$$EnhancerByCGLIB$$af0dd240.getConnector(<generated>)
    at org.apache.kafka.connect.runtime.AbstractHerder.connectorType(AbstractHerder.java:349)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerder$$EnhancerByCGLIB$$af0dd240.CGLIB$connectorType$23(<generated>)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerder$$EnhancerByCGLIB$$af0dd240$$FastClassByCGLIB$$8c31132d.invoke(<generated>)
    at org.easymock.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
    at org.easymock.internal.ClassProxyFactory$MockMethodInterceptor.intercept(ClassProxyFactory.java:92)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerder$$EnhancerByCGLIB$$af0dd240.connectorType(<generated>)
    at org.apache.kafka.connect.runtime.distributed.DistributedHerderTest.setUp(DistributedHerderTest.java:179)

Any hint is welcome.

Answer 1

I am a bit lost here but will still try to give some hints in terms of Socratic questions.

• Why do you need PowerMock for DistributedHerder ? It looks like a normal partial mocking
• And why PowerMock for Plugins instead of plain EasyMock?
• Do you have the PowerMock runner configured?
• What is herder.new ConfigUpdateListener() ? Which language is that?
• What is worker ?
• I see no replay() indeed. Can we have the full code?
• Nothing is recorded for backoff and updateDeletedConnectorStatus . Is that normal?
• In your case, it seems the plugins() method is returning null. This one isn't mocked so it probably just return null indeed no?