Guava Retry: Unable to test retry logic on InterruptedException

Question

AIM:

To test that when a certain function throws exception, it is retried X number of times.

CONSTRAINTS:

1. Need to use EasyMock (to have consistent mocking framework across unit tests)

CODE SNIPPET:

BUSINESS CODE

    import com.github.rholder.retry.Retryer;
    import com.github.rholder.retry.RetryerBuilder;

    class Retry {
    
        public Retryer<UserData> getRetryer() {
            return RetryerBuilder.<UserData>newBuilder()
                .retryIfException()
                .withWaitStrategy(waitStrategy()) //exponential with 3 attempts
                .withStopStrategy(stopStrategy())
                .withAttemptTimeLimiter(attemptTimeLimiter())
                .build();
        }
    }

    class UserClass
    {
        
        private final externalTeamLibrary; //and a constructor accepting it

        public publishSync(Some inputs, Retry retryParameters)
        {
            Callable<UserData> publishCallable =
                () -> publishAsync(Some inputs) //returns Future object
                         .get(retryParameters.callTimeOutInMs(), TimeUnit.MILLISECONDS);
            return retryParameters.getRetryer().call(publishCallable);
        }

        public Future<FutureData> publishAsync(Some inputs)
        {
            return externalTeamLibrary.send(obj1, obj2); //returns Future object
        }
    }

TEST CODE

    @Test
    public voide testFunction()
    {
        //real objects
        Retry realRetryInstance = // a way to get one
    
        //mocks
        ExternalTeamLibraryClass externalTeamLibraryMock=  createMock(ExternalTeamLibraryClass.class);
    
        //expectations and return values
        EasyMock.expect(externalTeamLibraryMock.send(anyObject(), anyObject()))
                .andThrow(new InterruptException("test1"))
                .times(3);
    
        EasyMock.replay(externalTeamLibraryMock);
    
        UserClass user = new UserClass(externalTeamLibraryMock, other stuff);
        user.publishSync(someRealInputs, realRetryInstance);
    
        //verify all mocks used
        EasyMock.verify(externalTeamLibraryMock);
    }

What I wanted to happen

On explicitly invoking publishSync and by making externalTeamLibrary.send() throw exception, I wanted real Retry object to 'retry' publishAsync(). The retry limit is 3, so I expect three invocations to externalTeamLibrary.send().

But I get following error.

StackTrace

---

[junit] Testcase: testFunction: Caused an ERROR
[junit] Retrying failed to complete successfully after 1 attempts.
[junit] com.github.rholder.retry.RetryException: Retrying failed to complete successfully after 1 attempts.
[junit]     at com.github.rholder.retry.Retryer.call(Retryer.java:181)
[junit]     at UserClass.publish
[junit]     at TestClass.testFunction
[junit] Caused by: org.apache.kafka.common.errors.InterruptException: test1
[junit]     at org.easymock.internal.MockInvocationHandler.invoke(MockInvocationHandler.java:46)
[junit]     at org.easymock.internal.ObjectMethodsFilter.invoke(ObjectMethodsFilter.java:94)
[junit]     at org.easymock.internal.ClassProxyFactory$MockMethodInterceptor.intercept(ClassProxyFactory.java:97)
[junit]     at externalTeamLibrary$$EnhancerByCGLIB$$f53a1a7e.send(<generated>)
[junit]     at UserClass.publishAsync(line:175)
[junit]     at UserClass.lambda$publish$1(lineZ:209)
[junit]     at com.github.rholder.retry.AttemptTimeLimiters$NoAttemptTimeLimit.call(AttemptTimeLimiters.java:78)
[junit]     at com.github.rholder.retry.Retryer.call(Retryer.java:160)
[junit] Caused by: java.lang.InterruptedException
[junit]     at org.apache.kafka.common.errors.InterruptException.<init>(InterruptException.java:35)
[junit]     at TestClass.testFunction

---

Error occurs on the line where I throw InterruptException

---

UPDATE 1

Just had an epiphany. If my external library mock throws something other than org.apache.kafka.common.errors.InterruptException, then retry fails with correct message Retrying failed to complete successfully after 3 attempts..

But when my mock throws InterruptException, then retry fails after first attempt itself. The point of failure in both cases are different. In the guava retry code. , line 174 is for happy case, where stop strategy was used. Line 181 is for negative case, where InterruptException is causing InterruptedException!

This link shows that kafka's InterruptException is just a wrapper on InterruptedException. So the real issue is how to successfully retry on it. If the thread got interrupted while trying to perform a task, I feel it is something that should be retried, because we don't know for sure its irrecoverable.