LESSON: Autowire Interface, Rather than Concrete Class

In one of my tests, my first version test code is like below:

@RunWith(SpringTestRunner.class)
@DataLoader(filePaths = { "fixture/versionedBasRequests.xls" }, loaderType = LoaderType.EXCEL)
@ContextConfiguration(locations = "classpath*:applicationContext.xml")
@ActiveProfiles("test")
@TransactionConfiguration(transactionManager = "transactionManager")
@Transactional
public class BasRequestDaoTest {

	@Autowired
	private BasRequestDao basRequestDao;

Note that BasRequestDao is the concrete class of interface IBasRequestDao, I wrote this because I need to test the concrete class,

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.star.integration.basbroker.dao.impl.BasRequestDaoTest': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.star.integration.basbroker.dao.impl.BasRequestDao com.star.integration.basbroker.dao.impl.BasRequestDaoTest.basBetRequestDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.star.integration.basbroker.dao.impl.BasRequestDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1146)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:376)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:110)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:312)
	at org.easetech.easytest.runner.SpringTestRunner.createTest(SpringTestRunner.java:407)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:288)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:284)
	at org.easetech.easytest.runner.SpringTestRunner.methodBlock(SpringTestRunner.java:366)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
	at org.easetech.easytest.runner.SpringTestRunner.runChild(SpringTestRunner.java:101)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.easetech.easytest.strategy.SerialScheduler.schedule(SerialScheduler.java:16)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.easetech.easytest.util.RunAftersWithOutputData.evaluate(RunAftersWithOutputData.java:111)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.star.integration.basbroker.dao.impl.BasRequestDao com.star.integration.basbroker.dao.impl.BasRequestDaoTest.basBetRequestDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.star.integration.basbroker.dao.impl.BasRequestDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:517)
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:286)
	... 27 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.star.integration.basbroker.dao.impl.BasRequestDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:988)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:858)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:489)
	... 29 more

Solution: autowire the interface

@RunWith(SpringTestRunner.class)
@DataLoader(filePaths = { "fixture/versionedBasRequests.xls" }, loaderType = LoaderType.EXCEL)
@ContextConfiguration(locations = "classpath*:applicationContext.xml")
@ActiveProfiles("test")
@TransactionConfiguration(transactionManager = "transactionManager")
@Transactional
public class BasRequestDaoTest {

	@Autowired
	private IBasRequestDao basRequestDao;