PowerMockito .when().thenReturn() with randomUUID 不返回预期值
PowerMockito .when().thenReturn() with randomUUID not returning expected value
我正在尝试测试连接到 SQL 服务器数据库的 Web 服务方法，该数据库包含 JCR 节点，因为我们正在使用 JackRabbit。
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;
}
其中 jsonResult 是一个与此类似的对象：
{
"id" : "<A random UUID>"
"version" : 1
}
现在，当我尝试按照 and the code in this post 中的步骤对其进行测试时，我得到了以下代码（正如我所说，它基于过去的 links）：
@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，当我测试这个方法时，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}>
如您所见，这两个 UUID 是不同的，从我在这个问题中的第一个 link 中读到的是，每次静态方法 UUID.randomUUID() 都应该 return 相同的 UUID ] 被调用（存储在 TestJackRabbitService class...
中的 uuid 变量中的那个
我也尝试使用 doReturn 方法，如 中所述，但它产生以下堆栈跟踪：
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.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.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access[=14=]0(ParentRunner.java:58)
at org.junit.runners.ParentRunner.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.call(DelegatingPowerMockRunner.java:149)
at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner.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)
从 我读到（但我不明白）也许我需要从我正在尝试测试的 class 创建一个新对象？我在测试 class 一开始就注入了依赖项，我对 JUnit 测试真的很陌生，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（由于我缺乏 JUnit 测试知识）。
如何让我的 JUnit 测试检索在方法内部生成的相同 ID（或拦截对 UUID.randomUUD() 的调用以 return 我的 JUnit 测试) ?
编辑
尝试@hammerfest 的回答后，进行了以下更改：
UUID uuid = PowerMockito.mock(UUID.class);
mockStatic(UUID.class);
when(UUID.randomUUID()).thenReturn(uuid);
String jsonToCompare = "{\"id\":\"" + uuid + "\",\"version\":1}";
String jsonFromJRS = jackRabbitService.addDocumentByJson(nameFile, bytes, nameApp, 5, jsonproperties);
assertEquals(jsonFromJRS, jsonToCompare);
我仍然得到这个结果：
testAddDocumentsByJson(com.optimissa.test.junit.TestJackRabbitService): expected:<{"id":"[493410b3-dd0b-4b78-97bf-289f50f6e74f]","version":1}> but was:<{"id":"[00000000-0000-0000-0000-000000000000]","version":1}>
我重用并修改了@hammerfest 的示例，它在我的机器上可以正常工作。
第一种情况简单地模拟了 UUID 的静态调用 class 并断言返回的 SUT 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，其中 returns 模拟 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 生成重构为实用程序 class，但您可以通过 Spring 实例化和注入这两个测试。然后你可以简单地用普通的 Mockito 模拟替换 PowerMock 的东西，避免处理这样的问题：
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（以进一步加快速度），您可以通过构造函数注入或通过 Whitebox.setInternalState(sut, "fieldName", mockObject); 或 [=45 自己注入依赖项=]s ReflectionUtils.setField(sut, "fieldName", mockObject);。
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();
}
}
}
最后一个测试包含两个选项，构造函数或字段注入，你可以玩。
由于@hammerfest 的评论，我在这里添加了一个进一步的示例，展示了如果 MyClass 是外部定义的，该怎么做。请注意，在我阅读@ArthurZagretdinov 的回答之前，这个示例基本上取自 Github，他可能首先是该测试的作者（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())));
}
}
如果您注释掉上述场景中的两个注释行，您会发现由于 UUID 不相等，测试将失败。这意味着 MyClass 的准备工作也尊重使用声明的 UUID 模拟，因此可用于模拟静态 classes.
模拟系统 classes 的常见错误是将它们添加到 @PrepareForTest，但不幸的是，不可能直接模拟最终 Java 系统 classes。但是PowerMock提供了workaround。 PowerMock 通过调用 PowerMock class 替换了对系统 classes 的调用。应将使用最终系统 class 的 class 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 中找到更多信息。
我正在尝试测试连接到 SQL 服务器数据库的 Web 服务方法，该数据库包含 JCR 节点，因为我们正在使用 JackRabbit。
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;
}
其中 jsonResult 是一个与此类似的对象：
{
"id" : "<A random UUID>"
"version" : 1
}
现在，当我尝试按照
@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，当我测试这个方法时，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}>
如您所见，这两个 UUID 是不同的，从我在这个问题中的第一个 link 中读到的是，每次静态方法 UUID.randomUUID() 都应该 return 相同的 UUID ] 被调用（存储在 TestJackRabbitService class...
uuid 变量中的那个
我也尝试使用 doReturn 方法，如
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.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.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access[=14=]0(ParentRunner.java:58)
at org.junit.runners.ParentRunner.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.call(DelegatingPowerMockRunner.java:149)
at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner.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)
从 JUnit 测试真的很陌生，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（由于我缺乏 JUnit 测试知识）。
如何让我的 JUnit 测试检索在方法内部生成的相同 ID（或拦截对 UUID.randomUUD() 的调用以 return 我的 JUnit 测试) ?
编辑
尝试@hammerfest 的回答后，进行了以下更改：
UUID uuid = PowerMockito.mock(UUID.class);
mockStatic(UUID.class);
when(UUID.randomUUID()).thenReturn(uuid);
String jsonToCompare = "{\"id\":\"" + uuid + "\",\"version\":1}";
String jsonFromJRS = jackRabbitService.addDocumentByJson(nameFile, bytes, nameApp, 5, jsonproperties);
assertEquals(jsonFromJRS, jsonToCompare);
我仍然得到这个结果：
testAddDocumentsByJson(com.optimissa.test.junit.TestJackRabbitService): expected:<{"id":"[493410b3-dd0b-4b78-97bf-289f50f6e74f]","version":1}> but was:<{"id":"[00000000-0000-0000-0000-000000000000]","version":1}>
我重用并修改了@hammerfest 的示例，它在我的机器上可以正常工作。
第一种情况简单地模拟了 UUID 的静态调用 class 并断言返回的 SUT 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，其中 returns 模拟 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 生成重构为实用程序 class，但您可以通过 Spring 实例化和注入这两个测试。然后你可以简单地用普通的 Mockito 模拟替换 PowerMock 的东西，避免处理这样的问题：
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（以进一步加快速度），您可以通过构造函数注入或通过 Whitebox.setInternalState(sut, "fieldName", mockObject); 或 [=45 自己注入依赖项=]s ReflectionUtils.setField(sut, "fieldName", mockObject);。
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();
}
}
}
最后一个测试包含两个选项，构造函数或字段注入，你可以玩。
由于@hammerfest 的评论，我在这里添加了一个进一步的示例，展示了如果 MyClass 是外部定义的，该怎么做。请注意，在我阅读@ArthurZagretdinov 的回答之前，这个示例基本上取自 Github，他可能首先是该测试的作者（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())));
}
}
如果您注释掉上述场景中的两个注释行，您会发现由于 UUID 不相等，测试将失败。这意味着 MyClass 的准备工作也尊重使用声明的 UUID 模拟，因此可用于模拟静态 classes.
模拟系统 classes 的常见错误是将它们添加到 @PrepareForTest，但不幸的是，不可能直接模拟最终 Java 系统 classes。但是PowerMock提供了workaround。 PowerMock 通过调用 PowerMock class 替换了对系统 classes 的调用。应将使用最终系统 class 的 class 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 中找到更多信息。