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Testing Error Propagation Mechanisms in Netflix Hystrix

This test suite validates error propagation functionality in Netflix’s Hystrix library using Spring Framework integration. It specifically tests how errors are handled and propagated through Hystrix commands when using Spring AOP with CGLIB proxies.

Test Coverage Overview

The test suite covers error propagation mechanisms in Hystrix commands within a Spring context.

Key areas tested include:

Basic error propagation scenarios using Spring AOP
Integration with Spring’s dependency injection
CGLIB-based proxy configuration
User service error handling patterns

Implementation Analysis

The testing approach leverages Spring’s test context framework with JUnit4 integration. It extends BasicErrorPropagationTest while implementing Spring-specific configurations.

Key patterns include:

Use of @RunWith(SpringJUnit4ClassRunner.class) for Spring test context
Context configuration using @ContextConfiguration
Dependency injection with @Autowired
Bean configuration using @Configurable and @Bean annotations

Technical Details

Testing tools and configuration:

JUnit4 testing framework
Spring Test Context Framework
AOP CGLIB configuration for proxy generation
Custom ErrorPropagationTestConfig class for bean definitions
Integration with Hystrix’s error propagation mechanisms

Best Practices Demonstrated

The test implementation showcases several testing best practices for Spring-based Hystrix applications.

Notable practices include:

Proper separation of concerns between test configuration and test cases
Use of dependency injection for test components
Clean inheritance structure for test case organization
Explicit configuration of AOP proxying strategy

netflix/hystrix

hystrix-contrib/hystrix-javanica/src/test/java/com/netflix/hystrix/contrib/javanica/test/spring/error/ErrorPropagationTest.java

            
/**
 * Copyright 2015 Netflix, Inc.
 * <p/>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.netflix.hystrix.contrib.javanica.test.spring.error;


import com.netflix.hystrix.contrib.javanica.test.common.error.BasicErrorPropagationTest;
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;

/**
 * Test covers "Error Propagation" functionality.
 * https://github.com/Netflix/Hystrix/wiki/How-To-Use#ErrorPropagation
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {AopCglibConfig.class, ErrorPropagationTest.ErrorPropagationTestConfig.class})
public class ErrorPropagationTest extends BasicErrorPropagationTest {


    @Autowired
    private BasicErrorPropagationTest.UserService userService;

    @Override
    protected UserService createUserService() {
        return userService;
    }


    @Configurable
    public static class ErrorPropagationTestConfig {

        @Bean
        public UserService userService() {
            return new UserService();
        }
    }
    
}