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Testing Observable Error Propagation Integration in Netflix Hystrix

This test suite validates error propagation functionality in Netflix Hystrix’s Observable patterns using Spring integration. It specifically examines how errors are handled and propagated through the Hystrix circuit breaker when using Observable commands within a Spring context.

Test Coverage Overview

The test suite provides comprehensive coverage of error propagation scenarios in Hystrix’s Observable implementation.

Key areas tested include:

Spring AOP integration with CGLIB
Observable command error handling
User service error propagation patterns
Spring context configuration validation

Implementation Analysis

The testing approach leverages Spring’s testing framework with JUnit4 integration. It extends BasicObservableErrorPropagationTest while implementing Spring-specific configurations and autowiring. The implementation uses Spring’s context configuration to validate error propagation in a dependency-injected environment.

Notable patterns include:

Spring runner configuration with @RunWith annotation
Context configuration using @ContextConfiguration
Dependency injection with @Autowired
Bean configuration through @Configurable

Technical Details

Testing tools and configuration:

SpringJUnit4ClassRunner for test execution
AopCglibConfig for aspect-oriented programming setup
Spring context configuration classes
JUnit 4 testing framework
Hystrix Observable command integration
Spring dependency injection framework

Best Practices Demonstrated

The test implementation showcases several testing best practices in Spring and Hystrix integration.

Notable practices include:

Clear separation of concerns between Spring configuration and test logic
Proper use of dependency injection in test scenarios
Structured error propagation testing
Extension of base test class for reusability
Proper Spring context configuration management

netflix/hystrix

hystrix-contrib/hystrix-javanica/src/test/java/com/netflix/hystrix/contrib/javanica/test/spring/error/ObservableErrorPropagationTest.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.BasicObservableErrorPropagationTest;
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, ObservableErrorPropagationTest.ErrorPropagationTestConfig.class})
public class ObservableErrorPropagationTest extends BasicObservableErrorPropagationTest {


    @Autowired
    private UserService userService;

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


    @Configurable
    public static class ErrorPropagationTestConfig {

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

}