unit-test-caching_skill

Overview

This skill provides concise, reusable patterns for unit testing Spring Cache annotations (@Cacheable, @CachePut, @CacheEvict) without booting a full Spring context. It focuses on fast, reliable tests using an in-memory CacheManager, mocks for dependencies, and explicit verification of cache hits, misses, and invalidation. Use it to validate cache configuration, key generation, and conditional caching behavior.

How this skill works

The skill shows how to replace external caches (Redis, etc.) with ConcurrentMapCacheManager in tests and how to configure @EnableCaching in a light test config. It uses Mockito to mock repositories and verifies repository invocation counts to assert cache hits and misses. Patterns cover @Cacheable caching, @CacheEvict invalidation and allEntries behavior, @CachePut updates, SpEL-based cache keys, and conditional caching with condition/unless.

When to use it

• Unit testing @Cacheable behavior and ensuring method execution is skipped on cache hit
• Validating @CacheEvict removes single keys or clears all entries
• Testing @CachePut updates cache entries after persistence operations
• Verifying custom cache key generation using SpEL expressions
• Testing conditional caching (condition and unless) and null-result handling

Best practices

• Use ConcurrentMapCacheManager or an in-memory cache for deterministic, fast tests
• Mock repositories and verify invocation counts (verify(times(n))) instead of relying on timing
• Reset or clear caches between tests (@BeforeEach or @DirtiesContext) to avoid cross-test leaks
• Test positive and negative paths: hits, misses, eviction, and conditional branches
• Ensure caching proxying is active in test config (@EnableCaching) and avoid direct self-invocation

Example use cases

• Assert getUserById is called once on repeated calls when @Cacheable is applied
• Confirm deleteProduct triggers @CacheEvict and subsequent reads hit repository again
• Validate updateOrder with @CachePut replaces cached value so subsequent reads return updated data
• Check InventoryService cache key '#productId + "-" + #warehouseId' generates distinct keys for different params
• Verify @Cacheable(unless = "#result == null") prevents caching of null repository results