Mockito如何mock靜態(tài)方法問題

更新時間：2025年02月25日 10:53:16 作者：cab5

本文介紹了如何在Mockito 3.4.0版本及以上版本中mock靜態(tài)方法,包括如何在pom文件中添加相關(guān)jar包、如何使用Mockito.mockStatic(Class mockClass)方法以及注意事項等

Mockito如何mock靜態(tài)方法

在實際工作當(dāng)中，我們經(jīng)常會遇到需要對靜態(tài)方法進(jìn)行 mock 的情況。在 mockito 2.x 的時代，我們需要借助 powmock 才能實現(xiàn)。

當(dāng) mockito 進(jìn)化到了 3.4.0 版本以后，也開始對靜態(tài)方法 mock 進(jìn)行了支持（主要是通過 mockito-inline 包）。

簡單的介紹就到這里，下面讓我們進(jìn)入主題吧。

1.首先確保pom文件中

mockito 相關(guān) jar 包的版本（這里我用的版本是 3.7.7），如下：

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-core</artifactId>
    <version>3.7.7</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-inline</artifactId>
    <version>3.7.7</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-junit-jupiter</artifactId>
    <version>3.7.7</version>
    <scope>test</scope>
</dependency>
<dependency>
     <groupId>junit</groupId>
     <artifactId>junit</artifactId>
     <version>4.13</version>
     <scope>test</scope>
 </dependency>

2.使用方式

Mockito.mockStatic(Class mockClass)，如下：

// 這里 DateUtil 內(nèi)提供了靜態(tài)方法
MockedStatic<DateUtil> dateUtil = mockStatic(DateUtil.class);

示例：

import static org.mockito.Mockito.mockStatic;

@RunWith(MockitoJUnitRunner.class)
public class AlphaServiceTest {

    @Test
    public void testHttp() {
        ...
        
        MockedStatic<HTTPClient> httpClient = mockStatic(HTTPClient.class);
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...
        
        // 關(guān)閉
        httpClient.close();
    }

這樣基本上就 OK 了。

唯一需要注意下的就是 httpClient.close()，這個問題會在「3.其他」中 “錯誤提示 static mocking is already registered in the current thread To create a new mock, the existing static mock registration must be deregistered” 進(jìn)行詳細(xì)說明）

3.其他

如果項目中未引入 mockito-inline，會出現(xiàn)如下錯誤信息：

org.mockito.exceptions.base.MockitoException:
The used MockMaker SubclassByteBuddyMockMaker does not support the creation of static mocks

Mockito's inline mock maker supports static mocks based on the Instrumentation API.
You can simply enable this mock mode, by placing the 'mockito-inline' artifact where you are currently using 'mockito-core'.
Note that Mockito's inline mock maker is not supported on Android.

   at com.annoroad.order.service.PreOrderServiceTestCase.testSaveClinicalFreeSuccess1(PreOrderServiceTestCase.java:86)
   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.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
   at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
   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:251)
   at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
   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$2.evaluate(ParentRunner.java:268)
   at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
   at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
   at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
   at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
   at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
   at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
   at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
   at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
   at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)

錯誤提示

static mocking is already registered in the current thread To create a new mock, the existing static mock registration must be deregistered

當(dāng)多個單元測試都使用了同一個 static mock 對象，且使用完成后都沒有進(jìn)行 close。此時，若這幾個單元測試用一起執(zhí)行，第一個單元測試占用了 static mock 對象，第二個單元測試就沒有辦法再占用了。

如果出現(xiàn)了這種情況，解決辦法也很簡單，就是關(guān)閉 static mock 對象，如下：

import static org.mockito.Mockito.mockStatic;

@RunWith(MockitoJUnitRunner.class)
public class AlphaServiceTest {

    @Test
    public void testHttp1() {
        ...
        
        MockedStatic<HTTPClient> httpClient = mockStatic(HTTPClient.class);
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...

		httpClient.close();
    }
    
    @Test
    public void testHttp2() {
        ...
        
        MockedStatic<HTTPClient> httpClient = mockStatic(HTTPClient.class);
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...

		httpClient.close();
    }
    
    @Test
    public void testHttp3() {
        ...
        
        MockedStatic<HTTPClient> httpClient = mockStatic(HTTPClient.class);
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...
		
		httpClient.close();
    }

如果你的很多單元測試中都用到了 mockStatic(HTTPClient.class)，且覺得在每個單元測試當(dāng)中都寫一遍 mockStatic()…close() 很低效，可以采用下邊的方式：

import static org.mockito.Mockito.mockStatic;

@RunWith(MockitoJUnitRunner.class)
public class AlphaServiceTest {
	private MockedStatic<HttpClietn> httpClient;

	// 每個單元測試啟動前，先執(zhí)行該方法（高版本中 @Before 被替換成 @BeforeEach）
    @Before
    public void setUp() {
        this.httpClient = mockStatic(HTTPClient.class);
    }
    
	// 每個單元測試執(zhí)行完成后，執(zhí)行該方法（高版本中 @After 被替換成 @AfterEach）
    @After
    public void teardown() {
        this.httpClient.close();
    }

    @Test
    public void testHttp1() {
        ...
        
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...
    }
    
    @Test
    public void testHttp2() {
        ...
        
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...
    }
    
    @Test
    public void testHttp3() {
        ...
        
        httpClient.when(() -> HTTPClient.sendPost("xxx/zzz/ccc", "hello")).thenReturn("success");
        
        ...
    }

這樣就清爽多了 ~：）