Snippet

Verifying Conditional Bean Registration with ApplicationContextRunner

The ApplicationContextRunner utility enables testing conditional configuration and bean registration rules in isolated contexts without bootstrapping a complete Spring Boot application. It creates an ephemeral context to execute assertions against bean existence, types, or configuration fallbacks.

snippet.java

java

class CacheAutoConfigurationTest {
 
    private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
        .withUserConfiguration(CacheAutoConfiguration.class);
 
    @Test
    void shouldRegisterInMemoryCacheWhenPropertySet() {
        contextRunner
            .withPropertyValues("app.cache.type=memory")
            .run(context -> {
                assertThat(context).hasSingleBean(InMemoryCache.class);
                assertThat(context).doesNotHaveBean(RedisCache.class);
            });
    }
 
    @Test
    void shouldBackOffWhenDisabled() {
        contextRunner
            .withPropertyValues("app.cache.enabled=false")
            .run(context -> assertThat(context).doesNotHaveBean(CacheManager.class));
    }
}

spring

Breakdown

private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().withUserConfiguration(CacheAutoConfiguration.class);

Configures an isolated non-web test context runner with the targeted configuration class.

.withPropertyValues("app.cache.type=memory")

Simulates environment properties to evaluate conditional annotations like @ConditionalOnProperty.

assertThat(context).hasSingleBean(InMemoryCache.class);

Asserts that exactly one matching bean exists in the dynamically evaluated context.

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Verifying Conditional Bean Registration with ApplicationContextRunner

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