【SpringBoot】Junit单元测试遇到的一些问题

情况 ①：不能有返回值

@Controller
public class FileControllerTest{

    @Autowired
    private FileController fileController;

    @Test
    public String testDownload(){
        fileController.download("2dd4209286df4f14b703890ccdc3d2ff");
        return "";
    }
}

报错：

java.lang.Exception: Method testDownload() should be void

	at org.junit.runners.model.FrameworkMethod.validatePublicVoid(FrameworkMethod.java:99)
	at org.junit.runners.model.FrameworkMethod.validatePublicVoidNoArg(FrameworkMethod.java:74)
	at org.junit.runners.ParentRunner.validatePublicVoidNoArgMethods(ParentRunner.java:155)
	...

解决办法：测试用例方法是不能有返回值的，必须是public void的。

情况 ②：NullPointerException

@Controller
public class FileControllerTest{

    @Autowired
    private FileController fileController;

    @Test
    public void testDownload(){
        fileController.download("2dd4209286df4f14b703890ccdc3d2ff");
    }
}

报错：

java.lang.NullPointerException 
	at com.yealink.version.controller.FileControllerTest.testDownload(FileControllerTest.java:20)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	...

解决办法：意味着要在测试类顶部加上注解@RunWith(SpringRunner.class)。

情况 ③： Bean注入失败

@RunWith(SpringRunner.class)
@Controller
public class FileControllerTest{

    @Autowired
    private FileController fileController;

    @Test
    public void testDownload(){
        fileController.download("2dd4209286df4f14b703890ccdc3d2ff");
    }
}

报错：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'com.yealink.version.controller.FileControllerTest': Unsatisfied dependency expressed through field 'fileController'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.yealink.version.controller.FileController' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:386)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.yealink.version.controller.FileController' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1493)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
	... 27 common frames omitted

解决办法：该错误意味着是注入失败，需要在测试类顶部加上注解@SpringBootTest(classes =VersionManagerApplicationForDev.class)，且这个启动类（VersionManagerApplicationForDev）需要进行扫描，即在启动类上加@SpringBootApplication注解。

情况 ④：找不到相应的启动配置

@RunWith(SpringRunner.class)
@SpringBootTest(classes = VersionManagerApplicationForDev.class)
@Controller
public class FileControllerTest{

    @Autowired
    private FileController fileController;

    @Test
    public void testDownload(){
        fileController.download("2dd4209286df4f14b703890ccdc3d2ff");
    }
}

报错：

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:873)
	at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4420)
	...

解决办法：这是因为我的项目中application.yml里面进行了多环境配置，如果有的没有相应的数据库会报错。因为可以在测试类顶部加上注解@ActiveProfiles("dev")选择需要的环境。

情况 ⑤：优化

@RunWith(SpringRunner.class)
@SpringBootTest(classes = VersionManagerApplicationForDev.class)
@ActiveProfiles("dev")
@Controller
public class FileControllerTest{

    @Autowired
    private FileController fileController;

    @Test
    public void testDownload(){
        fileController.download("2dd4209286df4f14b703890ccdc3d2ff");
    }
}

可以看到如果有很多的测试类，那么需要在每个测试类顶部加上这些注解也是很多余的，因此可以写成一个基类，让测试类继承基类即可，最后就变成了这样：

public class FileControllerTest extends BaseTest{

    @Autowired
    private FileController fileController;

    @Test
    public void testDownload(){
        fileController.download("2dd4209286df4f14b703890ccdc3d2ff");
    }
}

import com.yealink.version.VersionManagerApplicationForDev;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.junit4.SpringRunner;

/**
 * Created by yl1794 on 2018/6/6.
 */
@RunWith(SpringRunner.class)
@SpringBootTest(classes = VersionManagerApplicationForDev.class)
@ActiveProfiles("dev")
public class BaseTest {

}