unit-test-caching

name	unit-test-caching
description	Unit tests for caching behavior using Spring Cache annotations (@Cacheable, @CachePut, @CacheEvict). Use when validating cache configuration and cache hit/miss scenarios.
category	testing
tags	["junit-5","caching","cacheable","cache-evict","cache-put"]
version	1.0.1

Unit Testing Spring Caching

Test Spring caching annotations (@Cacheable, @CacheEvict, @CachePut) without full Spring context. Verify cache behavior, hits/misses, and invalidation strategies.

When to Use This Skill

Use this skill when:

• Testing @Cacheable method caching
• Testing @CacheEvict cache invalidation
• Testing @CachePut cache updates
• Verifying cache key generation
• Testing conditional caching
• Want fast caching tests without Redis or cache infrastructure

Setup: Caching Testing

Maven

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-test</artifactId>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>org.mockito</groupId>
  <artifactId>mockito-core</artifactId>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>org.assertj</groupId>
  <artifactId>assertj-core</artifactId>
  <scope>test</scope>
</dependency>

Gradle

dependencies {
  implementation("org.springframework.boot:spring-boot-starter-cache")
  testImplementation("org.springframework.boot:spring-boot-starter-test")
  testImplementation("org.mockito:mockito-core")
  testImplementation("org.assertj:assertj-core")
}

Basic Pattern: Testing @Cacheable

Cache Hit and Miss Behavior

// Service with caching
@Service
public class UserService {

  private final UserRepository userRepository;

  public UserService(UserRepository userRepository) {
    this.userRepository = userRepository;
  }

  @Cacheable("users")
  public User getUserById(Long id) {
    return userRepository.findById(id).orElse(null);
  }
}

// Test caching behavior
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.BeforeEach;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import static org.mockito.Mockito.*;
import static org.assertj.core.api.Assertions.*;

@Configuration
@EnableCaching
class CacheTestConfig {
  @Bean
  public CacheManager cacheManager() {
    return new ConcurrentMapCacheManager("users");
  }
}

class UserServiceCachingTest {

  private UserRepository userRepository;
   UserService userService;
   CacheManager cacheManager;

  
    {
    userRepository = mock(UserRepository.class);
    cacheManager =  ();
    userService =  (userRepository);
  }

  
    {
        (, );
    (userRepository.findById()).thenReturn(Optional.of(user));

       userService.getUserById();
       userService.getUserById();

    assertThat(firstCall).isEqualTo(secondCall);
    verify(userRepository, times()).findById(); 
  }

  
    {
        (, );
    (userRepository.findById()).thenReturn(Optional.of(user));

    userService.getUserById(); 
       userService.getUserById(); 

    assertThat(cachedResult).isEqualTo(user);
    verify(userRepository, times()).findById();
  }
}

Testing @CacheEvict

Cache Invalidation

@Service
public class ProductService {

  private final ProductRepository productRepository;

  public ProductService(ProductRepository productRepository) {
    this.productRepository = productRepository;
  }

  @Cacheable("products")
  public Product getProductById(Long id) {
    return productRepository.findById(id).orElse(null);
  }

  @CacheEvict("products")
  public void deleteProduct(Long id) {
    productRepository.deleteById(id);
  }

  @CacheEvict(value = "products", allEntries = true)
  public void clearAllProducts() {
    // Clear entire cache
  }
}

class ProductCacheEvictTest {

  private ProductRepository productRepository;
  private ProductService productService;
  private CacheManager cacheManager;

  @BeforeEach
  void setUp() {
    productRepository = mock(ProductRepository.class);
    cacheManager = new ConcurrentMapCacheManager("products");
    productService = new ProductService(productRepository);
  }

  @Test
  void shouldEvictProductFromCacheWhenDeleted() {
        (, , );
    (productRepository.findById()).thenReturn(Optional.of(product));

    productService.getProductById(); 

    productService.deleteProduct(); 

       userService.getUserById();
    
    
    verify(productRepository, times()).findById();
  }

  
    {
        (, , );
        (, , );
    (productRepository.findById()).thenReturn(Optional.of(product1));
    (productRepository.findById()).thenReturn(Optional.of(product2));

    productService.getProductById();
    productService.getProductById();

    productService.clearAllProducts(); 

    productService.getProductById();
    productService.getProductById();

    
    verify(productRepository, times()).findById();
    verify(productRepository, times()).findById();
  }
}

Testing @CachePut

Cache Update

@Service
public class OrderService {

  private final OrderRepository orderRepository;

  public OrderService(OrderRepository orderRepository) {
    this.orderRepository = orderRepository;
  }

  @Cacheable("orders")
  public Order getOrder(Long id) {
    return orderRepository.findById(id).orElse(null);
  }

  @CachePut(value = "orders", key = "#order.id")
  public Order updateOrder(Order order) {
    return orderRepository.save(order);
  }
}

class OrderCachePutTest {

  private OrderRepository orderRepository;
  private OrderService orderService;

  @BeforeEach
  void setUp() {
    orderRepository = mock(OrderRepository.class);
    orderService = new OrderService(orderRepository);
  }

  @Test
  void shouldUpdateCacheWhenOrderIsUpdated() {
    Order originalOrder = new Order(1L, "Pending", 100.0);
    Order updatedOrder = new Order(, , );

    (orderRepository.findById()).thenReturn(Optional.of(originalOrder));
    (orderRepository.save(updatedOrder)).thenReturn(updatedOrder);

    orderService.getOrder();
       orderService.updateOrder(updatedOrder);

    assertThat(result.getStatus()).isEqualTo();
    
    
       orderService.getOrder();
    assertThat(cachedOrder.getStatus()).isEqualTo();
  }
}

Testing Conditional Caching

Cache with Conditions

@Service
public class DataService {

  private final DataRepository dataRepository;

  public DataService(DataRepository dataRepository) {
    this.dataRepository = dataRepository;
  }

  @Cacheable(value = "data", unless = "#result == null")
  public Data getData(Long id) {
    return dataRepository.findById(id).orElse(null);
  }

  @Cacheable(value = "users", condition = "#id > 0")
  public User getUser(Long id) {
    return userRepository.findById(id).orElse(null);
  }
}

class ConditionalCachingTest {

  @Test
  void shouldNotCacheNullResults() {
    DataRepository dataRepository = mock(DataRepository.class);
    when(dataRepository.findById(999L)).thenReturn(Optional.empty());

    DataService service = new DataService(dataRepository);

    service.getData(999L);
    service.getData(999L);

    // Should call repository twice because null results are not cached
    verify(dataRepository, times(2)).findById(999L);
  }

  @Test
  void shouldNotCacheWhenConditionIsFalse {
       mock(UserRepository.class);
        (, );
    (userRepository.findById(-)).thenReturn(Optional.of(user));

        ();

    service.getUser(-);
    service.getUser(-);

    
    verify(userRepository, times()).findById(-);
  }
}

Testing Cache Keys

Verify Cache Key Generation

@Service
public class InventoryService {

  private final InventoryRepository inventoryRepository;

  public InventoryService(InventoryRepository inventoryRepository) {
    this.inventoryRepository = inventoryRepository;
  }

  @Cacheable(value = "inventory", key = "#productId + '-' + #warehouseId")
  public InventoryItem getInventory(Long productId, Long warehouseId) {
    return inventoryRepository.findByProductAndWarehouse(productId, warehouseId);
  }
}

class CacheKeyTest {

  @Test
  void shouldGenerateCorrectCacheKey() {
    InventoryRepository repository = mock(InventoryRepository.class);
    InventoryItem item = new InventoryItem(1L, 1L, 100);
    when(repository.findByProductAndWarehouse(1L, 1L)).thenReturn(item);

    InventoryService service = new InventoryService(repository);

    service.getInventory(1L, 1L); // Cache: "1-1"
    service.getInventory(1L, 1L); // Hit cache: "1-1"
    service.getInventory(, ); 

    verify(repository, times()).findByProductAndWarehouse(any(), any());
  }
}

Best Practices

• Use in-memory CacheManager for unit tests
• Verify repository calls to confirm cache hits/misses
• Test both positive and negative cache scenarios
• Test cache invalidation thoroughly
• Test conditional caching with various conditions
• Keep cache configuration simple in tests
• Mock dependencies that services use

Common Pitfalls

• Testing actual cache infrastructure instead of caching logic
• Not verifying repository call counts
• Forgetting to test cache eviction
• Not testing conditional caching
• Not resetting cache between tests

Troubleshooting

Cache not working in tests: Ensure @EnableCaching is in test configuration.

Wrong cache key generated: Use SpEL syntax correctly in @Cacheable(key = "...").

Cache not evicting: Verify @CacheEvict key matches stored key exactly.

References

• Spring Caching Documentation
• Spring Cache Abstractions
• SpEL in Caching