Spring-Data: Unknown entity with Java configuration

My project structure looks like

persistence/pom.xml
           src/main/java/
                        ApplicationConfig
                        NetworkRepository
                        NetworkRepositoryImpl
                        Network
           src/main/test/NetworkRepositoryTest

My ApplicationConfig looks like

@Configuration
@ComponentScan
@EnableJpaRepositories
public class ApplicationConfig {
    @Bean
    public DataSource dataSource() {
        final EmbeddedDatabaseBuilder embeddedDatabaseBuilder = new EmbeddedDatabaseBuilder();
        embeddedDatabaseBuilder.setType(EmbeddedDatabaseType.H2);
        return embeddedDatabaseBuilder.build();
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        final HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter();
        jpaVendorAdapter.setDatabase(Database.H2);
        jpaVendorAdapter.setGenerateDdl(true);

        final LocalContainerEntityManagerFactoryBean localContainerEntityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        localContainerEntityManagerFactoryBean.setJpaVendorAdapter(jpaVendorAdapter);
        localContainerEntityManagerFactoryBean.setPackagesToScan(getClass().getPackage().getName());
        localContainerEntityManagerFactoryBean.setDataSource(dataSource());
        localContainerEntityManagerFactoryBean.setPersistenceUnitName("test-comma-pu");

        return localContainerEntityManagerFactoryBean;
    }

    @Bean
    public PlatformTransactionManager transactionManager() {
        final JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
        return transactionManager;
    }
}

my Network entity looks like

import javax.annotation.Nonnull;
import javax.persistence.Entity;

import org.joda.time.DateTime;

@Entity
public class Network extends AbstractEntity {
    private final long networkId;

    private final String name;

    private final boolean active;

    private final DateTime createdAt;

    private String createdBy;

    private DateTime updatedAt;

    private String updatedBy;
...
}

My NetworkRepository looks like

import java.util.List;

import javax.annotation.Nonnull;

import org.springframework.data.repository.Repository;

import com.org.comma.persistence.entities.Network;

public interface NetworkRepository extends Repository<Network, Long> {
    @Nonnull
    List<Network> findAll();

    @Nonnull
    Network save(@Nonnull final Network network);
}

My NetworkRepositoryImpl looks like

@Repository
@Transactional
public class NetworkRepositoryImpl implements NetworkRepository {

    @PersistenceContext
    private EntityManager entityManager;

    @Override
    @Nonnull
    public List<Network> findAll() {
        return Collections.emptyList();
    }

    @Nonnull
    @Override
    public Network save(@Nonnull final Network network) {
        if (network.getId() == null) {
            entityManager.persist(network);
            return network;
        } else {
            return entityManager.merge(network);
        }
    }
}

and my Test looks like

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {ApplicationConfig.class, NetworkRepositoryImpl.class})
@Transactional
public class NetworkRepositoryTest {

    @Autowired
    NetworkRepository networkRepository;

    @Test
    public void testAllNetworks() {
        Network network = new Network(1, "US", true, DateTime.now());
        network = networkRepository.save(network);
        final List<Network> networks = networkRepository.findAll();
        assertTrue(networks.isEmpty());
    }
}

When I run test, I see error as

java.lang.IllegalArgumentException: Unknown entity: com.org.comma.persistence.entities.Network

I found people recommending to have persistence.xml, My question is when I am already using Java Based Configuration(ApplicationConfig) and also set the base packages to scan

localContainerEntityManagerFactoryBean.setPackagesToScan(getClass().getPackage().getName());

even in that case I need persistence.xml?