Android最佳Mock单元测试方案:Junit + Mockito + Powermock
hongxinkg1
8年前
<p>单元测试由一组独立的测试构成，每个测试针对软件中的一个单独的程序单元。单元测试并非检查程序单元之间是否能够合作良好，而是检查单个程序单元行为是否正确。</p> <h2>为什么要进行单元测试</h2> <p>在敏捷开发大行其道的今天，由于时间紧，任务重，过分依赖测试工程师以及下列原因，导致单元测试不被重视，在开发流程中处于一个可有可无的尴尬境地。</p> <ol> <li>浪费的时间太多</li> <li>软件开发人员不应参与单元测试</li> <li>我是很棒的程序员，不需要进行单元测试</li> <li>不管怎样，集成测试将会抓住所有的Bug</li> <li>单元测试效率不高</li> </ol> <p>那么单元测试是否正的可有可无呢？No! No! No!</p> <ol> <li>作为android客户端研发，在一个开发周期内，你负责的需求需要Web服务（API），和本地代码（JNI，Native Code）的支持，而你们的工作是同时进行的。</li> <li>你的需求开发完成了，但是由于需要在特定条件下才能触发，而这些条件在开发过程中很难去模拟，导致需求无法在所有场景下进行充分测试。举个例子，假设你在室内开发一个地图导航的Android应用，你需要在导航过程中，前方出现车祸，积水，施工等多种状况，怎么办？</li> <li>总结你过去的BUG，你会发现有些你以为写的很完善的逻辑，却在最后被发现有场景未覆盖，或者逻辑错误等问题。</li> <li>测试工程师给你报了一个BUG，你改完提交了，但是之后由于Merge失误导致代码丢失，或者其他人的修改导致你的BUG再次出现。直到测试工程师再次发现该BUG，并再次给你提出。</li> <li>你的开发进度很快，但是开发完成后，你会被BUG淹没。你持续不断的修改BUG，持续不断的加班，直至发布版本，身心俱疲。</li> <li>以前明明很正常的功能，在本次开发周期内，突然不能正常使用了。<br> …</li> </ol> <p>如果你也经常碰到以上问题，或者困扰，那么你需要持续不断的对项目进行 <strong>单元测试</strong> 。</p> <h2>Android单元测试简介</h2> <p>Android的单元测试分为两大类：</p> <p>1.Instrumentation</p> <p>通过Android系统的Instrumentation测试框架，我们可以编写测试代码，并且打包成APK，运行在Android手机上。</p> <p>优点： 逼真</p> <p>缺点： 很慢</p> <p>代表框架：JUnit(Android自带),espresso</p> <p>2.JUnit / Mock</p> <p>通过JUnit，以及第三方测试框架，我们可以编写测试代码，生成class文件，直接运行在JVM虚拟机中。</p> <p>优点： 很快。使用简单，方便。</p> <p>缺点： 不够逼真。比如有些硬件相关的问题，无法通过这些测试出来。</p> <p>代表框架： JUnit(标准),Robolectric, mockito, powermock</p> <h2>Android最佳Mock单元测试方案</h2> <p>我通过对比前辈们对各种单元测试框架的实践，总结出Android最佳Mock单元测试方案: Junit + Mockito + Powermock.（自己认证的…）</p> <h3>Junit + Mockito + Powermock 简介</h3> <p>众所周知，Junit是一个简单的单元测试框架。</p> <p>Mockito，则是一个简单的用于Mock的单元测试框架。</p> <p>那么为什么还需要Powermock呢？</p> <p>EasyMock和Mockito等框架，对static, final, private方法均是不能mock的。</p> <p>这些框架普遍是通过创建Proxy的方式来实现的mock。 而PowerMock是使用CGLib来操纵字节码而实现的mock，所以它能实现对上面方法的mock。</p> <h3>Junit + Mockito + Powermock 引入</h3> <p>由于PowerMock对Mockito有较强依赖，因此需要按照以下表格采用对应的版本。</p> <table> <thead> <tr> <th>Mockito</th> <th>PowerMock</th> </tr> </thead> <tbody> <tr> <td>2.0.0-beta - 2.0.42-beta</td> <td>1.6.5+</td> </tr> <tr> <td>1.10.8 - 1.10.x</td> <td>1.6.2+</td> </tr> <tr> <td>1.9.5-rc1 - 1.9.5</td> <td>1.5.0 - 1.5.6</td> </tr> <tr> <td>1.9.0-rc1 & 1.9.0</td> <td>1.4.10 - 1.4.12</td> </tr> <tr> <td>1.8.5</td> <td>1.3.9 - 1.4.9</td> </tr> <tr> <td>1.8.4</td> <td>1.3.7 & 1.3.8</td> </tr> <tr> <td>1.8.3</td> <td>1.3.6</td> </tr> <tr> <td>1.8.1 & 1.8.2</td> <td>1.3.5</td> </tr> <tr> <td>1.8</td> <td>1.3</td> </tr> <tr> <td>1.7</td> <td>1.2.5</td> </tr> </tbody> </table> <p>建议方案：</p> <p>在项目依赖文件build.gradle中添加以下依赖。</p> <pre> <code class="language-java">testCompile 'junit:junit:4.11' // required if you want to use Mockito for unit tests testCompile 'org.mockito:mockito-core:1.9.5' // required if you want to use Powermock for unit tests testCompile 'org.powermock:powermock-module-junit4:1.5.6' testCompile 'org.powermock:powermock-module-junit4-rule:1.5.6' testCompile 'org.powermock:powermock-api-mockito:1.5.6' </code></pre> <h3>Junit + Mockito + Powermock 配置</h3> <ol> <li>默认的测试代码位置<br> 对于通过gradle构建的android项目，在默认的项目结构中，Instrumentation的测试代码放在<br> src/androidTest/ 目录，而JUnit / Mock的测试代码放在 src/test/ 目录。</li> <li>自定义测试代码位置<br> 有些项目是由Eclipse构建迁移到由Gradle构建，需要自定义测试代码位置。<br> 举个例子，androidTest和test目录都在项目的根文件夹下。我们需要这样配置： <pre> <code class="language-java">android { sourceSets { test { java.srcDir 'test' } androidTest { java.srcDir 'androidTest' } } } </code></pre> </li> </ol> <p>如果在单元测试中遇到类似”Method … not mocked.”的问题，请添加以下设置：</p> <pre> <code class="language-java">android { // ... testOptions { unitTests.returnDefaultValues = true } } </code></pre> <h3>Junit + Mockito + Powermock 使用</h3> <p>强烈建议你熟读以下内容，来熟悉Junit + Mockito + Powermock的使用。</p> <ol> <li><a href="/misc/goto?guid=4959676264307677030" rel="nofollow,noindex">Mockito 中文文档 ( 2.0.26 beta )</a></li> <li><a href="/misc/goto?guid=4959676264396028452" rel="nofollow,noindex">Mockito reference documentation</a></li> <li><a href="/misc/goto?guid=4959676264476574721" rel="nofollow,noindex">powermock wiki</a></li> <li><a href="/misc/goto?guid=4959672183663539269" rel="nofollow,noindex">Unit tests with Mockito - Tutorial</a></li> </ol> <p>下面通过举例来简单说明Junit + Mockito + Powermock 使用，更多详情清参考Demo项目：</p> <p><a href="/misc/goto?guid=4959676264596101104" rel="nofollow,noindex">https://github.com/snowdream/test/tree/master/android/test/mocktest</a></p> <p>源码： <a href="/misc/goto?guid=4959676264680859177" rel="nofollow,noindex">https://github.com/snowdream/test/blob/master/android/test/mocktest/app/src/main/java/snowdream/github/com/mocktest/Calc.java</a></p> <p>测试代码： <a href="/misc/goto?guid=4959676264761276671" rel="nofollow,noindex">https://github.com/snowdream/test/blob/master/android/test/mocktest/app/src/test/java/snowdream/github/com/mocktest/CalcUnitTest.java</a></p> <p>1.验证某些行为,主要是验证某些函数是否被调用，以及被调用的具体次数。</p> <pre> <code class="language-java">//using mock mockedList.add("once"); mockedList.add("twice"); mockedList.add("twice"); mockedList.add("three times"); mockedList.add("three times"); mockedList.add("three times"); //following two verifications work exactly the same - times(1) is used by default // 下面的两个验证函数效果一样,因为verify默认验证的就是times(1) verify(mockedList).add("once"); verify(mockedList, times(1)).add("once"); //exact number of invocations verification // 验证具体的执行次数 verify(mockedList, times(2)).add("twice"); verify(mockedList, times(3)).add("three times"); //verification using never(). never() is an alias to times(0) // 使用never()进行验证,never相当于times(0) verify(mockedList, never()).add("never happened"); //verification using atLeast()/atMost() // 使用atLeast()/atMost() verify(mockedList, atLeastOnce()).add("three times"); verify(mockedList, atLeast(2)).add("five times"); verify(mockedList, atMost(5)).add("three times"); </code></pre> <p>2.验证执行顺序，主要验证某些函数是否按照预定顺序执行。</p> <pre> <code class="language-java">// A. Single mock whose methods must be invoked in a particular order // A. 验证mock一个对象的函数执行顺序 List singleMock = mock(List.class); //using a single mock singleMock.add("was added first"); singleMock.add("was added second"); //create an inOrder verifier for a single mock // 为该mock对象创建一个inOrder对象 InOrder inOrder = inOrder(singleMock); //following will make sure that add is first called with "was added first, then with "was added second" // 确保add函数首先执行的是add("was added first"),然后才是add("was added second") inOrder.verify(singleMock).add("was added first"); inOrder.verify(singleMock).add("was added second"); // B. Multiple mocks that must be used in a particular order // B .验证多个mock对象的函数执行顺序 List firstMock = mock(List.class); List secondMock = mock(List.class); //using mocks firstMock.add("was called first"); secondMock.add("was called second"); //create inOrder object passing any mocks that need to be verified in order // 为这两个Mock对象创建inOrder对象 InOrder inOrder = inOrder(firstMock, secondMock); //following will make sure that firstMock was called before secondMock // 验证它们的执行顺序 inOrder.verify(firstMock).add("was called first"); inOrder.verify(secondMock).add("was called second"); // Oh, and A + B can be mixed together at will </code></pre> <p>3.使用powermock必须使用两个annotation：</p> <pre> <code class="language-java">@RunWith(PowerMockRunner.class) @PrepareForTest({Calc.class}) publicclassCalcUnitTest{ } //PrepareForTest 后面要加准备被mock或stub的类，单个class直接()起来即可，多个用{}，并用逗号隔开。 </code></pre> <p>4.测试公开成员变量</p> <pre> <code class="language-java">@Test publicvoidtestPublicField(){ assertEquals(mCalc.mPublicField, 0); assertEquals(mCalc.mPublicFinalField, 0); assertEquals(Calc.mPublicStaticField, 0); assertEquals(Calc.mPublicStaticFinalField, 0); mCalc.mPublicField = 1; Calc.mPublicStaticField = 2; assertEquals(mCalc.mPublicField, 1); assertEquals(mCalc.mPublicFinalField, 0); assertEquals(Calc.mPublicStaticField, 2); } </code></pre> <p>5.测试公开成员方法</p> <pre> <code class="language-java">@Test publicvoidtestAddPublicMethod(){ //when when(mCalc.addPublic(anyInt(), anyInt())) .thenReturn(0) .thenReturn(1) .thenReturn(2) .thenReturn(3) .thenReturn(4) .thenReturn(5); //call method for(inti =0; i <6; i++) { //verify assertEquals(mCalc.addPublic(i, i), i); } //verify verify(mCalc, times(6)).addPublic(anyInt(), anyInt()); verify(mCalc, atLeast(1)).addPublic(anyInt(), anyInt()); verify(mCalc, atLeastOnce()).addPublic(anyInt(), anyInt()); verify(mCalc, atMost(6)).addPublic(anyInt(), anyInt()); } </code></pre> <p>6.测试公开无返回值成员方法</p> <pre> <code class="language-java">@Test publicvoidtestAddPublicVoidMethod(){ //when doNothing().when(mCalc).voidPublic(anyInt(), anyInt()); mCalc.voidPublic(anyInt(), anyInt()); mCalc.voidPublic(anyInt(), anyInt()); verify(mCalc, atLeastOnce()).voidPublic(anyInt(), anyInt()); verify(mCalc, atLeast(2)).voidPublic(anyInt(), anyInt()); } </code></pre> <p>7.测试公开静态成员方法</p> <pre> <code class="language-java">@Test publicvoidtestAddPublicStaicMethod()throwsException{ PowerMockito.mockStatic(Calc.class); PowerMockito.when(Calc.class, "addPublicStatic", anyInt(), anyInt()) .thenReturn(0) .thenReturn(1) .thenReturn(2) .thenReturn(3) .thenReturn(4) .thenReturn(5); //call method for(inti =0; i <6; i++) { //verify assertEquals(Calc.addPublicStatic(i, i), i); } //verify static PowerMockito.verifyStatic(times(6)); } </code></pre> <p>8.测试私有成员变量</p> <p>Powermock提供了一个Whitebox的class，可以方便的绕开权限限制，可以get/set private属性，实现注入。也可以调用private方法。也可以处理static的属性/方法，根据不同需求选择不同参数的方法即可。</p> <pre> <code class="language-java">@Test publicvoidtestPrivateField()throwsIllegalAccessException{ PowerMockito.mockStatic(Calc.class); assertEquals(Whitebox.getField(Calc.class, "mPrivateField").getInt(mCalc),0); assertEquals(Whitebox.getField(Calc.class, "mPrivateFinalField").getInt(mCalc),0); assertEquals(Whitebox.getField(Calc.class, "mPrivateStaticField").getInt(null),0); assertEquals(Whitebox.getField(Calc.class, "mPrivateStaticFinalField").getInt(null),0); Whitebox.setInternalState(mCalc, "mPrivateField",1); Whitebox.setInternalState(Calc.class, "mPrivateStaticField",1, Calc.class); assertEquals(Whitebox.getField(Calc.class, "mPrivateField").getInt(mCalc),1); assertEquals(Whitebox.getField(Calc.class, "mPrivateFinalField").getInt(mCalc),0); assertEquals(Whitebox.getField(Calc.class, "mPrivateStaticField").getInt(null),1); assertEquals(Whitebox.getField(Calc.class, "mPrivateStaticFinalField").getInt(null),0); } </code></pre> <p>9.测试私有成员方法</p> <pre> <code class="language-java">@Test publicvoidtestAddPrivateMethod()throwsException{ PowerMockito.mockStatic(Calc.class); //when PowerMockito.when(mCalc,"addPrivate",anyInt(),anyInt()) .thenReturn(0) .thenReturn(1) .thenReturn(2) .thenReturn(3) .thenReturn(4) .thenReturn(5); //call method for(inti =0; i <6; i++) { //verify assertEquals(Whitebox.invokeMethod(mCalc,"addPrivate",i,i), i); } //verify static PowerMockito.verifyPrivate(mCalc,times(6)).invoke("addPrivate",anyInt(),anyInt()); PowerMockito.verifyPrivate(mCalc,atLeast(1)).invoke("addPrivate",anyInt(),anyInt()); } </code></pre> <p>10.测试私有静态成员方法</p> <pre> <code class="language-java">@Test publicvoidtestAddPrivateStaicMethod()throwsException{ PowerMockito.mockStatic(Calc.class); PowerMockito.when(Calc.class, "addPrivateStatic", anyInt(), anyInt()) .thenReturn(0) .thenReturn(1) .thenReturn(2) .thenReturn(3) .thenReturn(4) .thenReturn(5); //call method for(inti =0; i <6; i++) { //verify assertEquals(Whitebox.invokeMethod(Calc.class,"addPrivateStatic",i, i), i); } //verify static PowerMockito.verifyStatic(times(6)); } </code></pre> <p>通过以上介绍，相信你对Android项目的Mock单元测试有一定的了解。</p> <p>如果你有任何相关疑问，请通过以下方式联系我：</p> <p>Email：yanghui1986527#gmail.com</p> <p>QQ 群: 529327615</p> <h2>参考</h2> <ol> <li><a href="/misc/goto?guid=4959676264851317224" rel="nofollow,noindex">详细讲解单元测试的内容</a></li> <li><a href="/misc/goto?guid=4959676264929066098" rel="nofollow,noindex">浅谈单元测试的意义</a></li> <li><a href="/misc/goto?guid=4959676265019963993" rel="nofollow,noindex">敏捷开发之测试</a></li> <li><a href="/misc/goto?guid=4958865751774418439" rel="nofollow,noindex">Unit testing support</a></li> <li><a href="/misc/goto?guid=4959670563914923239" rel="nofollow,noindex">junit4</a></li> <li><a href="/misc/goto?guid=4958864743859781664" rel="nofollow,noindex">mockito</a></li> <li><a href="/misc/goto?guid=4959646068745187412" rel="nofollow,noindex">powermock</a></li> <li><a href="/misc/goto?guid=4959676264596101104" rel="nofollow,noindex">mocktest</a></li> <li><a href="/misc/goto?guid=4959676265227047944" rel="nofollow,noindex">在Android Studio中进行单元测试和UI测试</a></li> <li><a href="/misc/goto?guid=4959676265309176667" rel="nofollow,noindex">whats-the-best-mock-framework-for-java</a></li> <li><a href="/misc/goto?guid=4959676265405607641" rel="nofollow,noindex">mock测试</a></li> <li><a href="/misc/goto?guid=4959676265488047882" rel="nofollow,noindex">使用PowerMock来Mock静态函数</a></li> <li><a href="/misc/goto?guid=4959676265570880607" rel="nofollow,noindex">PowerMock介绍</a></li> <li><a href="/misc/goto?guid=4959676265657463148" rel="nofollow,noindex">Sharing code between unit tests and instrumentation tests on Android</a></li> <li><a href="/misc/goto?guid=4959672183663539269" rel="nofollow,noindex">Unit tests with Mockito - Tutorial</a></li> <li><a href="/misc/goto?guid=4959676265747243172" rel="nofollow,noindex">Android单元测试之Mockito浅析</a></li> <li><a href="/misc/goto?guid=4959676265836240486" rel="nofollow,noindex">Mockito 简明教程</a></li> <li><a href="/misc/goto?guid=4959676265920251969" rel="nofollow,noindex">mockito简单教程</a></li> </ol> <p> </p> <p>来自：http://snowdream.github.io/blog/2016/08/03/android-mock-test/</p> <p> </p>