PowerMockito .when（）。thenReturn（），randomUUID未返回预期值

时间：2017-06-29 15:54:06

标签： java spring junit uuid powermockito

我正在尝试测试连接到包含JCR节点的SQL Server数据库的Web服务方法，因为我们正在使用JackRabbit。

该方法如下：

public String addDocumentByJson(String fileName, byte[] fileContent, int status, String userName, String jsonProperties) {
    UUID id = UUID.randomUUID();
    // It does a bunch of operations here
    return jsonResult;
}

jsonResult是与此类似的对象：

{
    "id" : "<A random UUID>"
    "version" : 1
}

现在，当我尝试按照this answer中的步骤和this post中的代码进行测试时，我发现了以下代码（正如我所说的基于过去的链接）： 

@PrepareForTest({ UUID.class })
@RunWith(PowerMockRunner.class)
@PowerMockRunnerDelegate(SpringJUnit4ClassRunner.class)
@ContextConfiguration("/TestSpringConfig.xml")
public class TestJackRabbitService {

    @Autowired
    @Qualifier("jackRabbitService")
    IJackRabbitService jackRabbitService;

    private byte[] fileContent;
    private int versionFile;

    public TestJackRabbitService() {
        classLoader = getClass().getClassLoader();
    }
    @BeforeClass
    public static void init() {
        LOG.trace("Run @BeforeClass");
        try {
            fileContent = IOUtils.toByteArray(new FileInputStream(new File(Thread.currentThread().getContextClassLoader().getResource("fileTest.txt"))));
        } catch (Exception e) {
            LOG.error(ExceptionUtils.getStackTrace(e));
        }
    }

    @Before
    public void before() {
        LOG.trace("Run @Before");
        try {
            versionFile = jackRabbitService.getLastVersionOf(nameApp, nameFile); //This method returns an int,
        } catch (Exception e) {
            LOG.error(ExceptionUtils.getStackTrace(e));
        }
    }

    @Test
    public void testAddDocumentsByJson() {
        //Some tests which run correctly

        final UUID uuid = UUID.randomUUID();
        mockStatic(UUID.class);
        LOG.debug(uuid);
        //doReturn(uuid).when(UUID.randomUUID());
        when(UUID.randomUUID()).thenReturn(uuid);
        idFile = uuid;

        assertEquals(jackRabbitService.addDocumentByJson(nameFile, bytes, nameApp, 5, jsonproperties), "{\"id\":\"" + uuid + "\",\"version\":1}");
    }
}

然而，当我测试这种方法时，它给出了以下结果：

Results :

Failed tests: 
    testAddDocumentsByJson(com.optimissa.test.junit.TestJackRabbitService): expected:<{"id":"[1efaf3b8-ca7c-4e6f-878f-102d9a7a92d9]","version":1}> but was:<{"id":"[cfa1a8b0-be6a-46b1-90f5-d2f6d230796a]","version":1}>

正如你所看到的，两个UUID都不同，而且我在这个问题的第一个链接上读到的是每次调用静态方法UUID.randomUUID()时它应该返回相同的UUID（存储在{ {1}}类中的{1}}变量...

我也尝试使用this answer中解释的uuid方法，但它产生了以下堆栈跟踪：

TestJackRabbitService

来自this answer我读过（但我不明白），也许我需要从我尝试测试的课程中创建一个新对象？我在测试课的最开始时注入依赖项，我对doReturn测试很新，英语不是我的母语，但是我能理解大部分内容，但答案是让我很难理解它（由于我在JUnit测试中缺乏知识）。

如何使我的testAddDocumentsByJson(com.optimissa.test.junit.TestJackRabbitService) Time elapsed: 5.279 sec <<< ERROR! org.mockito.exceptions.misusing.UnfinishedStubbingException: Unfinished stubbing detected here: -> at com.optimissa.test.junit.TestJackRabbitService.testAddDocumentsByJson(TestJackRabbitService.java:143) E.g. thenReturn() may be missing. Examples of correct stubbing: when(mock.isOk()).thenReturn(true); when(mock.isOk()).thenThrow(exception); doThrow(exception).when(mock).someVoidMethod(); Hints: 1. missing thenReturn() 2. you are trying to stub a final method, which is not supported 3: you are stubbing the behaviour of another mock inside before 'thenReturn' instruction if completed at org.powermock.core.MockGateway.doMethodCall(MockGateway.java:182) at org.powermock.core.MockGateway.doMethodCall(MockGateway.java:164) at org.powermock.core.MockGateway.methodCall(MockGateway.java:134) at com.optimissa.test.junit.TestJackRabbitService.testAddDocumentsByJson(TestJackRabbitService.java:143) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252) 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.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) 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.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner$2.call(DelegatingPowerMockRunner.java:149) at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner$2.call(DelegatingPowerMockRunner.java:141) at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner.withContextClassLoader(DelegatingPowerMockRunner.java:132) at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner.run(DelegatingPowerMockRunner.java:141) at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:121) at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:57) at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59) at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252) at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141) at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189) at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165) at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85) at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115) at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75) 测试检索在方法内生成的相同ID（或拦截对JUnit的调用以返回JUnit测试中的值）？

修改

在尝试@ hammerfest的答案后，进行了以下更改：

UUID.randomUUD()

我仍然得到这个结果：

JUnit

2 个答案:

答案 0 :(得分：7)

模拟系统类的常见错误是它们被添加到@PrepareForTest，但不幸的是，直接模拟最终的Java System类是不可能的。但是PowerMock提供了workaround。 PowerMock通过调用PowerMock类替换对系统类的调用。应将使用最终系统类的类添加到@PrepareForTest

我添加了example如何模拟UUID。 

public class DocumentService {

  public JsonDocument saveDocument(JsonDocument document){
    UUID uuid = UUID.randomUUID();
    document.setId(uuid.toString());
    return document;
  }
}

测试

@RunWith(PowerMockRunner.class)
@PrepareForTest(DocumentService.class)
public class DocumentServiceTest {
@Test
public void should_set_id() throws Exception {
    final String id = "493410b3-dd0b-4b78-97bf-289f50f6e74f";
    UUID uuid = UUID.fromString(id);

    mockStatic(UUID.class);
    when(UUID.randomUUID()).thenReturn(uuid);

    DocumentService documentService = new DocumentService();

    JsonDocument document = new JsonDocument();
    documentService.saveDocument(document);

    assertThat(document.getId())
        .as("Id is set")
        .isEqualTo(id);
  }
}

您可以在documentation找到更多信息。

答案 1 :(得分：2)

我已经重新使用并修改了@hammerfest的示例，它可以在我的机器上运行。

第一种情况只是模拟UUID类的静态调用，并声明返回的SUT的UUID等于模拟的UUID：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import java.util.UUID;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.when;

@PrepareForTest({ UUID.class })
@RunWith(PowerMockRunner.class)
public class StaticMockTest {

  @Test
  public void test() {
    MyClass sut = new MyClass();

    UUID uuidLocal = UUID.randomUUID();
    mockStatic(UUID.class);
    when(UUID.randomUUID()).thenReturn(uuidLocal);

    assertThat(sut.getUUID(), is(equalTo(uuidLocal)));
  }

  private class MyClass {

    public UUID getUUID() {
      return UUID.randomUUID();
    }
  }
}

第二种情况调用Spring托管bean的方法，该方法返回模拟的UUID：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PowerMockIgnore;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.powermock.modules.junit4.PowerMockRunnerDelegate;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.BootstrapWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.context.support.AnnotationConfigContextLoader;
import org.springframework.test.context.support.DefaultTestContextBootstrapper;

import java.util.UUID;

import javax.annotation.Resource;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.when;

@PrepareForTest({ UUID.class })
@RunWith(PowerMockRunner.class)
@PowerMockRunnerDelegate(SpringRunner.class)
@BootstrapWith(DefaultTestContextBootstrapper.class)
@ContextConfiguration(classes = {StaticMockTest2.ContextConfig.class},
    loader= AnnotationConfigContextLoader.class)
@PowerMockIgnore({"javax.management.*"})
public class StaticMockTest2 {

  @Resource
  private MyClass sut;

  @Test
  public void test() {

    UUID uuidLocal = UUID.randomUUID();
    mockStatic(UUID.class);
    when(UUID.randomUUID()).thenReturn(uuidLocal);

    assertThat(sut.getUUID(), is(equalTo(uuidLocal)));
  }

  private static class MyClass {

    public UUID getUUID() {
      return UUID.randomUUID();
    }
  }

  @Configuration
  public static class ContextConfig {

    @Bean
    public MyClass myClass() {
      return new MyClass();
    }
  }
}

虽然我建议将UUID生成重构为一个实用程序类，然后通过Spring进行实例化和注入，但这两个测试都可以在我的机器上运行。然后你可以简单地用普通的Mockito模拟替换PowerMock的东西，避免处理这些问题：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.context.support.AnnotationConfigContextLoader;

import java.util.UUID;

import javax.annotation.Resource;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import static org.mockito.Mockito.mock;
import static org.powermock.api.mockito.PowerMockito.when;

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = {MockTest3.ContextConfig.class},
    loader= AnnotationConfigContextLoader.class)
public class MockTest3 {

  @Resource
  private Util mockUtil;
  @Resource
  private MyClass sut;

  @Test
  public void test() {

    UUID uuidLocal = UUID.randomUUID();
    when(mockUtil.generateUUID()).thenReturn(uuidLocal);

    assertThat(sut.getUUID(), is(equalTo(uuidLocal)));
  }

  private static class MyClass {

    private Util util;

    public MyClass(Util util) {
      this.util = util;
    }

    public UUID getUUID() {
      return util.generateUUID();
    }
  }

  private static class Util {

    public UUID generateUUID() {
      return UUID.randomUUID();
    }
  }

  @Configuration
  public static class ContextConfig {

    @Bean
    public Util mockUtil() {
      return mock(Util.class);
    }

    @Bean
    public MyClass myClass() {
      return new MyClass(mockUtil());
    }
  }
}

如果您不想依赖Spring进行测试（为了进一步加速），您可以通过构造函数注入或通过Whitebox.setInternalState(sut, "fieldName", mockObject);或Springs ReflectionUtils.setField(sut, "fieldName", mockObject);自己注入依赖项。 

import org.junit.Test;
import org.mockito.internal.util.reflection.Whitebox;

import java.util.UUID;

import javax.annotation.Resource;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import static org.mockito.Mockito.mock;
import static org.powermock.api.mockito.PowerMockito.when;

public class MockTest4 {

  @Test
  public void test() {

    Util mockUtil = mock(Util.class);
    MyClass sut = new MyClass(mockUtil);

//    MyClass sut = new MyClass();
//    Whitebox.setInternalState(sut, "util", mockUtil);

    UUID uuidLocal = UUID.randomUUID();
    when(mockUtil.generateUUID()).thenReturn(uuidLocal);

    assertThat(sut.getUUID(), is(equalTo(uuidLocal)));
  }

  private class MyClass {

    @Resource
    private Util util;

    public MyClass() {}
    public MyClass(Util util) {
      this.util = util;
    }

    public UUID getUUID() {
      return util.generateUUID();
    }
  }

  private class Util {

    public UUID generateUUID() {
      return UUID.randomUUID();
    }
  }
}

最后一个测试包含选项，构造函数或字段注入，您可以使用。

由于@hammerfest的评论我在这里添加了另一个例子，展示了如果MyClass是外部定义的，该怎么做。请注意，在我阅读@ArthurZagretdinov的答案之前，这个例子基本上是从Github获取的，@ArthurZagretdinov可能是这个测试的作者（正如@hammerfest在评论中指出的那样）。首先是独立的MyClass实现：

import java.util.UUID;

public class MyClass {

  public UUID getUUID() {
    return UUID.randomUUID();
  }
}

接下来，使用外部MyClass定义的测试：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import java.util.UUID;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.when;

@PrepareForTest({ MyClass.class })
@RunWith(PowerMockRunner.class)
public class StaticMockTest3 {

  @Test
  public void test() {
    MyClass sut = new MyClass();

    final String id = "493410b3-dd0b-4b78-97bf-289f50f6e74f";
    UUID uuid = UUID.fromString(id);

    // UUID uuidLocal = UUID.randomUUID();
    mockStatic(UUID.class);
    when(UUID.randomUUID()).thenReturn(uuidLocal);
    // when(UUID.randomUUID()).thenReturn(uuidLocal);

    assertThat(sut.getUUID().toString(), is(equalTo(uuid.toString())));
  }
}

如果您在上面的cenario中注释掉两个注释行，您将发现测试将因UUID不相等而失败。这意味着MyClass的准备工作也尊重使用声明的UUID模拟，因此可以用于模拟静态类。

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