Autowiring beans implementing same interface - how to autowire a particular dependency bean in a JUnit Test?

Question

I have a Spring 3.1/Java/Tomcat application. I have a service class that is as follows:

public class SomeServiceImpl implements SomeService {

  @Autowired
  public AnotherService anotherService;

  //  other code...

This uses another service class AnotherService which is autowired. Both these services classes are declared in a serviceContext.xml file.

I am writing junit to test SomeServiceImpl and use autowired to inject the class under test (SomeService) as well as the mock (EasyMock) dependency required by class under test (AnotherService). The easymock dependency for AnotherService is defined in a testContext.xml like below:

    <bean id="mockAnotherService" class="org.easymock.EasyMock" factory-method="createMock" primary="true">
        <constructor-arg value="com.xyz.AnotherService" />
    </bean>

In my test class I configure to use both the context files. However, I am seeing that the ServiceImpl is correctly wired to the actual implementation (this is desired) but instead of mock version of AnotherService the concreate version (AnotherServiceImpl) is getting wired.

How do I get the mocked version of my dependency wired instead? I can not use @Resource or @Qualifier in the actual implementation as that would defeat the purpose. I am ok to use these in my test class.

score 2 · Answer 1 · answered May 11 '12 at 15:10

2

If they're both declared in serviceContext.xml, and you want to mock one of them, then that file is no use for testing. Either split it so that you can use one of the 'real' Spring context files combined with a test context containing the mocks, or just create the bean manually and set the AnotherService using a setter method. One of the advantages of Inversion of Control is to allow you to create beans by hand and inject the dependencies that way.

answered May 11 '12 at 15:10

artbristol

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Agreed, and a good practice to make this easier is to make `SomeServiceImpl.anotherService` private, initialize it in the constructor, and use constructor injection by annotating the constructor as `Autowired`. Then, when you test against the mock, create the `SomeServiceImpl` manually rather than relying on Spring. – Kkkev May 13 '12 at 19:52

gkamal · Answer 2 · 2012-05-11T16:50:46.643

Instead of configuring to use both context file can you import your serviceContext.xml into the testContext.xml and then only refer the textContext.xml in your test case.

When you import a configuration file into another file the other file gets an opportunity to override the bean definition in the imported file.

Make sure the id of the mock is same as your class - otherwise it will create two different beans. Another issue is that the mock object doesn't advertise the correct interface type - so autowiring by type might fail. To get around that issue you would need to do something like the following. I am using this approach with mockito - should work for easy mock as well.

<bean id="anotherService" class="org.springframework.aop.framework.ProxyFactoryBean">
    <property name="target">
     <bean class="org.easymock.EasyMock" factory-method="createMock" primary="true">
        <constructor-arg value="com.xyz.AnotherService" />
    </bean>
    </property>
    <property name="proxyInterfaces">
      <value>com.xyz.AnotherService</value>
    </property>
  </bean>

Another thing to try would be to create Java Config style methods in your class that create mock objects. If creating this directly in the test class doesn't work you can have another class with @Configuration with the method to create the mock and then define that as a bean in your testContext.xml

  @Bean
  AnotherService anotherService() {
      return EasyMock.createMock(AnotherService.class);
  }

this seems to work in the sense that it does override the concrete bean and a mock gets wired, however, when I invoke any methods on the mock like replay, reset, verify it throws java.lang.IllegalArgumentException: Not a mock: $Proxy34. I guess EasyMock is not able to resolve the type of proxy. — Nilesh, May 11 '12 at 15:40
Did you try without the ProxyFactoryBean? i.e., Import the serviceContext.xml in the testContext.xml and assign the same id to the mock — gkamal, May 11 '12 at 16:47

Autowiring beans implementing same interface - how to autowire a particular dependency bean in a JUnit Test?

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