JUnit test with EhCache3

Question

I created simple caching application as below:

import org.ehcache.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.cache.CacheException;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public class JsonObjectCacheManager {
    private static final Logger logger = LoggerFactory.getLogger(JsonObjectCacheManager.class);
    private final Cache<String, JsonObjectWrapper> objectCache;

    //setting up cache
    public JsonObjectCacheManager() {
        CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder()
                .withCache("jsonCache",
                        CacheConfigurationBuilder.newCacheConfigurationBuilder(String.class, JsonObjectWrapper.class,
                                ResourcePoolsBuilder.newResourcePoolsBuilder()
                                        .heap(100, EntryUnit.ENTRIES)
                                        .offheap(10, MemoryUnit.MB))
                                .withExpiry(Expirations.timeToLiveExpiration(Duration.of(5, TimeUnit.MINUTES)))
                                .withValueSerializingCopier()
                                .build())
                .build(true);

        objectCache = cacheManager.getCache("jsonCache", String.class, JsonObjectWrapper.class);
    }

    public void putInCache(String key, Object value) {
        try {
            JsonObjectWrapper objectWrapper = new JsonObjectWrapper(value);
            objectCache.put(key, objectWrapper);
        } catch (CacheException e) {
            logger.error(String.format("Problem occurred while putting data into cache: %s", e.getMessage()));
        }
    }

    public Object retrieveFromCache(String key) {
        try {
            JsonObjectWrapper objectWrapper = objectCache.get(key);
            if (objectWrapper != null)
                return objectWrapper.getJsonObject();
        } catch (CacheException ce) {
            logger.error(String.format("Problem occurred while trying to retrieveSpecific from cache: %s", ce.getMessage()));
        }
        logger.error(String.format("No data found in cache."));
        return null;
    }

    public boolean isKeyPresent(String key){
        return objectCache.containsKey(key);
    }

}

JsonObjectWrapper is just a wrapper class to wrap the Object so that it is possible to serialize it.

@Getter
@Setter
@ToString
@AllArgsConstructor
public class JsonObjectWrapper implements Serializable {
    private static final long serialVersionUID = 3588889322413409158L;
    private Object jsonObject;
}

I've written the JUnit test as below:

import org.junit.*;
import org.mockito.*;

import java.util.*;

import static org.junit.Assert.*;

@RunWith(MockitoJUnitRunner.class)
public class JsonObjectCacheManagerTest {

    private JsonObjectCacheManager cacheManager;

    private Map<String, Object> names;

    @Before
    public void setup(){
        /*names = new HashMap(){
            {
                    put("name1", "Spirit Air Lines");
                    put("name2", "American Airlines");
                    put("name3", "United Airlines");
                }
            };*/

        //edited as per Henri's point and worked
        names = new HashMap();
        names.put("name1", "Spirit Air Lines");
        names.put("name2", "American Airlines");
        names.put("name3", "United Airlines");
           cacheManager = new JsonObjectCacheManager();
        }
    @Test
    public void isPresentReturnsTrueIfObjectsPutInCache() throws Exception {
        //put in cache
        cacheManager.putInCache("names",names);
        assertTrue(cacheManager.isKeyPresent("names"));
    }

    @Test
    public void cacheTest() throws Exception {
        //put in cache
        cacheManager.putInCache("names",names);

        //retrieve from cache
        Map<String, Object> namesFromCache = (Map<String, Object>) cacheManager.retrieveFromCache("names");
        //validate against the cached object
//        assertEquals(3, namesFromCache.size());
//        assertEquals("American Airlines", namesFromCache.get("name2"));

    }
}

I'm getting assertion error saying key is not present in cache. This means object is not being added to cache.

Is there any way to do junit test for this? Thanks for help.

Edit: Hey guys, @Henri pointed out my mistake and it solved my problem. :)

Answer 1

The problem is your HashMap. The way you instantiate it creates an anonymous inner class. Which keeps a reference to the outer class instance. Which is the test class. And the test class isn't serializable.

If you use the following code, all tests are passing nicely.

    names = new HashMap();
    names.put("name1", "Spirit Air Lines");
    names.put("name2", "American Airlines");
    names.put("name3", "United Airlines");

Answer 2

@Test
public void cacheTest() throws Exception {
    cacheManager = Mockito.mock(JsonObjectCacheManager.class);

You must not mock the class under test.