How can I unit-test javanica @HystrixCommand annotated methods?

Question

I am using javanica and annotating my hystrix command methods like this:

@HystrixCommand(groupKey="MY_GROUP", commandKey="MY_COMMAND" fallbackMethod="fallbackMethod")
public Object getSomething(Object request) {
....

And I am trying to unit tests my fallback methods, without having to call them directly, i.e. I would like to call the @HystrixCommand annotated method and let it flow naturally into the fallback after throwing a 500 error. This all works outside of unit tests.

In my unit tests I am using springs MockRestServiceServer to return 500 errors, this part is working, but Hystrix is not being initialized correctly on my unit tests. At the beginning of my test method I have:

HystrixRequestContext context = HystrixRequestContext.initializeContext();
myService.myHystrixCommandAnnotatedMethod();

After this I am trying to get any hystrix command by key and checking if there are any executed commands but the list is always empty, I am using this method:

public static HystrixInvokableInfo<?> getHystrixCommandByKey(String key) {
    HystrixInvokableInfo<?> hystrixCommand = null;
    System.out.println("Current request is " + HystrixRequestLog.getCurrentRequest());
    Collection<HystrixInvokableInfo<?>> executedCommands = HystrixRequestLog.getCurrentRequest()
            .getAllExecutedCommands();
    for (HystrixInvokableInfo<?> command : executedCommands) {
        System.out.println("executed command is " + command.getCommandGroup().name());
        if (command.getCommandKey().name().equals(key)) {
            hystrixCommand = command;
            break;
        }
    }
    return hystrixCommand;
}

I realize I am missing something in my unit tests initialization, can anyone point me in the right direction on how I can properly unit-test this?

Answer 1

Although you shouldn't necessarily UNIT test hystrix command. It's still useful to have a sort of spring hybrid test, I think point blank accepting the functionality when adding the annotation isn't correct. The test I created ensures that the circuit breaker opens on an exception.

@RunWith(SpringRunner.class)
@SpringBootTest
public class HystrixProxyServiceTests {

    @MockBean
    private MyRepo myRepo;

    @Autowired
    private MyService myService;

    private static final String ID = “1”;

    @Before
    public void setup() {
        resetHystrix();
        openCircuitBreakerAfterOneFailingRequest();
    }

    @Test
    public void circuitBreakerClosedOnSuccess() throws IOException, InterruptedException {

        when(myRepo.findOneById(USER_ID1))
        .thenReturn(Optional.of(Document.builder().build()));

        myService.findOneById(USER_ID1);
        HystrixCircuitBreaker circuitBreaker = getCircuitBreaker();
        Assert.assertTrue(circuitBreaker.allowRequest());

        verify(myRepo, times(1)).findOneById(
            any(String.class));
    }

    @Test
    public void circuitBreakerOpenOnException() throws IOException, InterruptedException {

        when(myRepo.findOneById(ID))
            .thenThrow(new RuntimeException());

        try {
            myService.findOneById(ID);
        } catch (RuntimeException exception) {
            waitUntilCircuitBreakerOpens();
            HystrixCircuitBreaker circuitBreaker = getCircuitBreaker();
            Assert.assertFalse(circuitBreaker.allowRequest());
        }

        verify(myRepo, times(1)).findOneById(
            any(String.class));
    }

    private void waitUntilCircuitBreakerOpens() throws InterruptedException {
        Thread.sleep(1000);
    }

    private void resetHystrix() {
        Hystrix.reset();
    }

    private void warmUpCircuitBreaker() {
        myService.findOneById(USER_ID1);
    }

    public static HystrixCircuitBreaker getCircuitBreaker() {
        return HystrixCircuitBreaker.Factory.getInstance(getCommandKey());
    }

    private static HystrixCommandKey getCommandKey() {
        return HystrixCommandKey.Factory.asKey("findOneById");
    }

    private void openCircuitBreakerAfterOneFailingRequest() {

        ConfigurationManager.getConfigInstance().
            setProperty("hystrix.command.findOneById.circuitBreaker.requestVolumeThreshold", 1);
    }

}

Another little thing that tripped me up for a while was that I had entered the default annotations without a specific command key, however when the command keys are created they are created against the method name which is what I've specified above. For a complete example I've also added the annotation to show I didn't specify a commandKey.

@HystrixCommand
public Optional<Document> findOneById(final String id) {
    return this.myRepo.findOneById(id);
}

Hope this helps someone.