unit-test-caching

Unit Testing Spring Caching

Overview

This skill provides patterns for unit testing Spring caching annotations (@Cacheable, @CacheEvict, @CachePut) without full Spring context. It covers cache hits/misses, invalidation, key generation, and conditional caching using in-memory ConcurrentMapCacheManager.

When to Use

• Writing unit tests for @Cacheable method behavior
• Verifying @CacheEvict cache invalidation works correctly
• Testing @CachePut cache updates
• Validating cache key generation from SpEL expressions
• Testing conditional caching with unless/condition parameters
• Mocking cache managers in fast unit tests without Redis

Instructions

1. Configure in-memory CacheManager: Use ConcurrentMapCacheManager for tests
2. Set up test fixtures: Mock repository and create service instance in @BeforeEach
3. Verify repository call counts: Use times(n) assertions to confirm cache behavior
4. Test cache hit: Call method twice, verify repository called once
5. Test cache miss: Verify repository called on each invocation
6. Test eviction: After @CacheEvict, verify repository called again on next read
7. Test key generation: Verify compound keys from SpEL expressions
8. Validate conditional caching: Test unless (null results) and condition (parameter-based)

Validation checkpoints:

• Run test → If cache not working: verify @EnableCaching annotation present
• If proxy issues: ensure method calls go through Spring proxy (no direct this calls)
• If key mismatches: log actual cache key and compare with @Cacheable(key="...") expression

Examples

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>

Gradle

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