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Testing Default Fallback Mechanisms for Hystrix Commands in Netflix/Hystrix

This test suite validates the default fallback functionality in Netflix Hystrix when used with Spring AOP and CGLIB. It extends BasicDefaultFallbackTest to verify both standard service fallbacks and command-specific fallbacks in a Spring context.

Test Coverage Overview

The test suite provides comprehensive coverage of Hystrix’s default fallback mechanisms within a Spring environment.

Tests service-level default fallbacks
Validates command-specific fallback behavior
Ensures proper Spring bean autowiring and configuration
Verifies AOP integration with CGLIB proxies

Implementation Analysis

The implementation leverages Spring’s testing framework with JUnit integration to validate Hystrix fallback patterns.

Key technical aspects include:

Uses SpringJUnit4ClassRunner for test execution
Implements context configuration with AopCglibConfig
Extends BasicDefaultFallbackTest for core fallback scenarios
Utilizes Spring’s dependency injection for service components

Technical Details

Spring Test Context framework
JUnit test runner
CGLIB-based AOP configuration
@Configurable annotation for bean definitions
@ContextConfiguration for test context setup
@Autowired for dependency injection

Best Practices Demonstrated

The test class exemplifies several testing best practices for Spring-based Hystrix applications.

Clean separation of configuration and test logic
Proper use of Spring’s testing infrastructure
Effective inheritance pattern for reusing test scenarios
Clear bean configuration through Java-based configuration

netflix/hystrix

hystrix-contrib/hystrix-javanica/src/test/java/com/netflix/hystrix/contrib/javanica/test/spring/fallback/DefaultFallbackTest.java

            
package com.netflix.hystrix.contrib.javanica.test.spring.fallback;

import com.netflix.hystrix.contrib.javanica.test.common.fallback.BasicDefaultFallbackTest;
import com.netflix.hystrix.contrib.javanica.test.spring.conf.AopCglibConfig;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.context.annotation.Bean;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * Created by dmgcodevil.
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {AopCglibConfig.class, DefaultFallbackTest.Config.class})
public class DefaultFallbackTest extends BasicDefaultFallbackTest {

    @Autowired
    private ServiceWithDefaultFallback serviceWithDefaultFallback;
    @Autowired
    private ServiceWithDefaultCommandFallback serviceWithDefaultCommandFallback;


    @Override
    protected ServiceWithDefaultFallback createServiceWithDefaultFallback() {
        return serviceWithDefaultFallback;
    }

    @Override
    protected ServiceWithDefaultCommandFallback serviceWithDefaultCommandFallback() {
        return serviceWithDefaultCommandFallback;
    }

    @Configurable
    public static class Config {
        @Bean
        public ServiceWithDefaultFallback serviceWithDefaultFallback() {
            return new ServiceWithDefaultFallback();
        }

        @Bean
        public ServiceWithDefaultCommandFallback serviceWithDefaultCommandFallback() {
            return new ServiceWithDefaultCommandFallback();
        }
    }
}