[FIXED] How to test @Cacheable?

Issue

I am struggling with testing @Cacheable within a Spring Boot Integration Test. This is my second day learning how to do Integration Tests and all of the examples I have found use older versions. I also saw an example of assetEquals("some value", is()) but nothing with an import statement to know which dependency "is" belongs to. The test fails at the second

This is my integration test....

@RunWith(SpringRunner.class)
@DataJpaTest // used for other methods
@SpringBootTest(classes = TestApplication.class)
@SqlGroup({
        @Sql(executionPhase = ExecutionPhase.BEFORE_TEST_METHOD,
                scripts = "classpath:data/Setting.sql") })
public class SettingRepositoryIT {

    @Mock
    private SettingRepository settingRepository;

    @Autowired
    private Cache applicationCache;


    @Test
    public void testCachedMethodInvocation() {
        List<Setting> firstList = new ArrayList<>();
        Setting settingOne = new Setting();
        settingOne.setKey("first");
        settingOne.setValue("method invocation");
        firstList.add(settingOne);

        List<Setting> secondList = new ArrayList<>();
        Setting settingTwo = new Setting();
        settingTwo.setKey("second");
        settingTwo.setValue("method invocation");
        secondList.add(settingTwo);

        // Set up the mock to return *different* objects for the first and second call
        Mockito.when(settingRepository.findAllFeaturedFragrances()).thenReturn(firstList, secondList);

        // First invocation returns object returned by the method
        List<Setting> result = settingRepository.findAllFeaturedFragrances();
        assertEquals("first", result.get(0).getKey());

        // Second invocation should return cached value, *not* second (as set up above)
        List<Setting> resultTwo = settingRepository.findAllFeaturedFragrances();
        assertEquals("first", resultTwo.get(0).getKey()); // test fails here as the actual is "second."

        // Verify repository method was invoked once
        Mockito.verify(settingRepository, Mockito.times(1)).findAllFeaturedFragrances();
        assertNotNull(applicationCache.get("findAllFeaturedFragrances"));

        // Third invocation with different key is triggers the second invocation of the repo method
        List<Setting> resultThree = settingRepository.findAllFeaturedFragrances();
        assertEquals(resultThree.get(0).getKey(), "second");
    }
}

ApplicationContext, components, entities, repositories and service layer for tests. The reason why I do it this way is because this maven module is used in other modules as a dependency.

@ComponentScan({ "com.persistence_common.config", "com.persistence_common.services" })
@EntityScan(basePackages = { "com.persistence_common.entities" })
@EnableJpaRepositories(basePackages = { "com.persistence_common.repositories" })
@SpringBootApplication
public class TestApplication {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Cache config....

@Configuration
@EnableCaching
public class CacheConfig {

    public static final String APPLICATION_CACHE = "applicationCache";

    @Bean
    public FilterRegistrationBean registerOpenSessionInViewFilterBean() {
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        OpenEntityManagerInViewFilter filter = new OpenEntityManagerInViewFilter();
        registrationBean.setFilter(filter);
        registrationBean.setOrder(5);
        return registrationBean;
    }


    @Bean
    public Cache applicationCache() {
        return new GuavaCache(APPLICATION_CACHE, CacheBuilder.newBuilder()
                .expireAfterWrite(30, TimeUnit.DAYS)
                .build());
    }
}

The repository under test....

public interface SettingRepository extends JpaRepository<Setting, Integer> {

    @Query(nativeQuery = true, value = "SELECT * FROM Setting WHERE name = 'featured_fragrance'")
    @Cacheable(value = CacheConfig.APPLICATION_CACHE, key = "#root.methodName")
    List<Setting> findAllFeaturedFragrances();
}

Solution

The first problem with SettingRepositoryIT is, the @Mock anotation on the field settingRepository. This is paradox for any normal-test, integration-test or any else.

You should let Spring bring in the dependencies for the class-under-test, which is SettingRepository in your case.

Please look at this example how @Autowired is used for the class-under-test, which is OrderService in this example:

@RunWith(SpringRunner.class)
// ApplicationContext will be loaded from the
// static nested Config class
@ContextConfiguration
public class OrderServiceTest {

    @Configuration
    static class Config {

        // this bean will be injected into the OrderServiceTest class
        @Bean
        public OrderService orderService() {
            OrderService orderService = new OrderServiceImpl();
            // set properties, etc.
            return orderService;
        }
    }

    @Autowired
    private OrderService orderService;

    @Test
    public void testOrderService() {
        // test the orderService
    }

}

Go for the documentation with the full example: § 15. Integration Testing

The second problem is that you do not have to test @Cachable. You should only test your implementation. Here is a very good example from Oliver Gierke on how you should test it: How to test Spring's declarative caching support on Spring Data repositories?

Answered By - Tobias Otto
Answer Checked By - David Marino (JavaFixing Volunteer)