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Testing Hystrix Fallback Property Inheritance Implementation in Netflix/Hystrix

This test suite validates the behavior of default properties and fallback configurations in Netflix’s Hystrix circuit breaker library. It focuses on verifying property inheritance and override patterns between default configurations and fallback methods.

Test Coverage Overview

The test suite provides comprehensive coverage of Hystrix’s fallback configuration mechanisms.

Key areas tested include:

Default property inheritance in fallback methods
Property override behaviors between commands and fallbacks
Thread pool configuration validation
Command group and key management

Integration points focus on the interaction between @DefaultProperties and @HystrixCommand annotations.

Implementation Analysis

The testing approach employs JUnit framework with a structured inheritance pattern using BasicHystrixTest as the base class. Tests utilize annotation-based configuration with @HystrixCommand and @DefaultProperties to define behavior patterns.

Key implementation patterns include:

Abstract test class design for flexible service creation
Systematic verification of property inheritance
Command and thread pool property validation

Technical Details

Testing tools and configuration:

JUnit test framework
Hystrix Command annotations
HystrixThreadPoolProperties for thread pool configuration
Custom utility methods for command retrieval
Abstract service pattern for test implementation

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Clear separation of concerns between test cases
Systematic property verification
Comprehensive edge case coverage
Well-structured test hierarchy
Proper use of setup methods
Consistent assertion patterns

netflix/hystrix

hystrix-contrib/hystrix-javanica/src/test/java/com/netflix/hystrix/contrib/javanica/test/common/configuration/fallback/BasicFallbackDefaultPropertiesTest.java

            
package com.netflix.hystrix.contrib.javanica.test.common.configuration.fallback;

import com.netflix.hystrix.HystrixThreadPoolProperties;
import com.netflix.hystrix.contrib.javanica.annotation.DefaultProperties;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import com.netflix.hystrix.contrib.javanica.test.common.BasicHystrixTest;
import org.junit.Before;
import org.junit.Test;

import static com.netflix.hystrix.contrib.javanica.conf.HystrixPropertiesManager.EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS;
import static com.netflix.hystrix.contrib.javanica.test.common.CommonUtils.getHystrixCommandByKey;
import static org.junit.Assert.assertEquals;


public abstract class BasicFallbackDefaultPropertiesTest extends BasicHystrixTest {

    private Service service;

    protected abstract Service createService();

    @Before
    public void setUp() throws Exception {
        service = createService();
    }

    @Test
    public void testFallbackInheritsDefaultGroupKey() {
        service.commandWithFallbackInheritsDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackInheritsDefaultProperties");
        assertEquals("DefaultGroupKey", fallbackCommand.getCommandGroup().name());
    }

    @Test
    public void testFallbackInheritsDefaultThreadPoolKey() {
        service.commandWithFallbackInheritsDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackInheritsDefaultProperties");
        assertEquals("DefaultThreadPoolKey", fallbackCommand.getThreadPoolKey().name());
    }

    @Test
    public void testFallbackInheritsDefaultCommandProperties() {
        service.commandWithFallbackInheritsDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackInheritsDefaultProperties");
        assertEquals(456, fallbackCommand.getProperties().executionTimeoutInMilliseconds().get().intValue());
    }

    @Test
    public void testFallbackInheritsThreadPollProperties() {
        service.commandWithFallbackInheritsDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackInheritsDefaultProperties");

        HystrixThreadPoolProperties properties = getThreadPoolProperties(fallbackCommand);

        assertEquals(123, properties.maxQueueSize().get().intValue());
    }

    @Test
    public void testFallbackOverridesDefaultGroupKey() {
        service.commandWithFallbackOverridesDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackOverridesDefaultProperties");
        assertEquals("FallbackGroupKey", fallbackCommand.getCommandGroup().name());
    }

    @Test
    public void testFallbackOverridesDefaultThreadPoolKey() {
        service.commandWithFallbackOverridesDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackOverridesDefaultProperties");
        assertEquals("FallbackThreadPoolKey", fallbackCommand.getThreadPoolKey().name());
    }

    @Test
    public void testFallbackOverridesDefaultCommandProperties() {
        service.commandWithFallbackOverridesDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackOverridesDefaultProperties");
        assertEquals(654, fallbackCommand.getProperties().executionTimeoutInMilliseconds().get().intValue());
    }

    @Test
    public void testFallbackOverridesThreadPollProperties() {
        service.commandWithFallbackOverridesDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackOverridesDefaultProperties");

        HystrixThreadPoolProperties properties = getThreadPoolProperties(fallbackCommand);

        assertEquals(321, properties.maxQueueSize().get().intValue());
    }

    @Test
    public void testCommandOverridesDefaultPropertiesWithFallbackInheritsDefaultProperties(){
        service.commandOverridesDefaultPropertiesWithFallbackInheritsDefaultProperties();
        com.netflix.hystrix.HystrixInvokableInfo fallbackCommand = getHystrixCommandByKey("fallbackInheritsDefaultProperties");
        HystrixThreadPoolProperties properties = getThreadPoolProperties(fallbackCommand);
        assertEquals("DefaultGroupKey", fallbackCommand.getCommandGroup().name());
        assertEquals("DefaultThreadPoolKey", fallbackCommand.getThreadPoolKey().name());
        assertEquals(456, fallbackCommand.getProperties().executionTimeoutInMilliseconds().get().intValue());
        assertEquals(123, properties.maxQueueSize().get().intValue());
    }

    @DefaultProperties(groupKey = "DefaultGroupKey",
            threadPoolKey = "DefaultThreadPoolKey",
            commandProperties = {
                    @HystrixProperty(name = EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS, value = "456")
            },
            threadPoolProperties = {
                    @HystrixProperty(name = "maxQueueSize", value = "123")
            })
    public static class Service {

        @HystrixCommand(fallbackMethod = "fallbackInheritsDefaultProperties")
        public Object commandWithFallbackInheritsDefaultProperties() {
            throw new RuntimeException();
        }

        @HystrixCommand(fallbackMethod = "fallbackOverridesDefaultProperties")
        public Object commandWithFallbackOverridesDefaultProperties() {
            throw new RuntimeException();
        }

        @HystrixCommand(groupKey = "CommandGroupKey",
                threadPoolKey = "CommandThreadPoolKey",
                commandProperties = {
                        @HystrixProperty(name = EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS, value = "654")
                },
                threadPoolProperties = {
                        @HystrixProperty(name = "maxQueueSize", value = "321")
                }, fallbackMethod = "fallbackInheritsDefaultProperties")
        public Object commandOverridesDefaultPropertiesWithFallbackInheritsDefaultProperties() {
            throw new RuntimeException();
        }

        @HystrixCommand
        private Object fallbackInheritsDefaultProperties() {
            return null;
        }

        @HystrixCommand(groupKey = "FallbackGroupKey",
                threadPoolKey = "FallbackThreadPoolKey",
                commandProperties = {
                        @HystrixProperty(name = EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS, value = "654")
                },
                threadPoolProperties = {
                        @HystrixProperty(name = "maxQueueSize", value = "321")
                })
        private Object fallbackOverridesDefaultProperties() {
            return null;
        }
    }
}