在多个文件上使用Power Mock运行Robolectric测试时出现ClassCastException异常

Question

所以我在这里根据参考指南设置了power mock .这一切似乎都可以通过单个测试类完美运行.但是当执行多个JUnit测试时,我在第二个测试类上遇到以下错误.

正如您从下面的堆栈跟踪中看到的,我正在尝试模拟一个otto Bus实例.它似乎在第一个测试类上正确模拟,但在第二个类上我得到了这个类转换异常.

在堆栈跟踪上我得到了禁用Objenisis缓存的建议,但我不知道如何实现这一点,如果这实际上是根本原因,因为我正在使用classloading-xstream:1.6.2根据上面附带的Robolectric Wiki链接.

如果我运行一个JUnit测试类,那么我的设置很有效,但是一旦我尝试在一个包中运行所有测试,只有第一个测试可以工作,后续测试将获得类强制转换异常.

org.mockito.exceptions.base.MockitoException: 
    ClassCastException occurred while creating the mockito proxy :
      class to mock : 'com.squareup.otto.Bus', loaded by classloader : 'org.robolectric.internal.bytecode.InstrumentingClassLoader@1593948d'
      created class : 'com.squareup.otto.Bus$$EnhancerByMockitoWithCGLIB$$82a3b196', loaded by classloader : 'org.robolectric.internal.bytecode.InstrumentingClassLoader@1593948d'
      proxy instance class : 'com.squareup.otto.Bus$$EnhancerByMockitoWithCGLIB$$82a3b196', loaded by classloader : 'org.mockito.internal.creation.util.SearchingClassLoader@618ff5c2'
      instance creation by : ObjenesisInstantiator

    You might experience classloading issues, disabling the Objenesis cache *might* help (see MockitoConfiguration)
        at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:61)
        at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:49)
        at org.powermock.api.mockito.repackaged.CglibMockMaker.createMock(CglibMockMaker.java:24)
        at org.powermock.api.mockito.internal.mockmaker.PowerMockMaker.createMock(PowerMockMaker.java:45)
        at com.acme.android.myapp.services.gcm.handlers.RequestLogoutHandlerTest.setup(RequestLogoutHandlerTest.java:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        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.RunBefores.evaluate(RunBefores.java:24)
        at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:251)
        at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:188)
        at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:54)
        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.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:152)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
        at org.junit.runners.Suite.runChild(Suite.java:128)
        at org.junit.runners.Suite.runChild(Suite.java:27)
        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.runners.ParentRunner.run(ParentRunner.java:363)
        at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
        at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78)
        at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212)
        at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
    Caused by: java.lang.ClassCastException: Cannot cast com.squareup.otto.Bus$$EnhancerByMockitoWithCGLIB$$82a3b196 to com.squareup.otto.Bus
        at java.lang.Class.cast(Class.java:3369)
        at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:59)
        at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:49)
        at org.powermock.api.mockito.repackaged.CglibMockMaker.createMock(CglibMockMaker.java:24)
        at org.powermock.api.mockito.internal.mockmaker.PowerMockMaker.createMock(PowerMockMaker.java:45)
        at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:33)
        at org.mockito.internal.MockitoCore.mock(MockitoCore.java:59)
        at org.mockito.Mockito.mock(Mockito.java:1285)
        at org.mockito.Mockito.mock(Mockito.java:1163)
        ... 36 more


    org.mockito.exceptions.base.MockitoException: 
    ClassCastException occurred while creating the mockito proxy :
      class to mock : 'com.squareup.otto.Bus', loaded by classloader : 'org.robolectric.internal.bytecode.InstrumentingClassLoader@1593948d'
      created class : 'com.squareup.otto.Bus$$EnhancerByMockitoWithCGLIB$$82a3b196', loaded by classloader : 'org.robolectric.internal.bytecode.InstrumentingClassLoader@1593948d'
      proxy instance class : 'com.squareup.otto.Bus$$EnhancerByMockitoWithCGLIB$$82a3b196', loaded by classloader : 'org.mockito.internal.creation.util.SearchingClassLoader@618ff5c2'
      instance creation by : ObjenesisInstantiator

    You might experience classloading issues, disabling the Objenesis cache *might* help (see MockitoConfiguration)
        at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:61)
        at org.powermock.api.mockito.repackaged.ClassImposterizer.imposterise(ClassImposterizer.java:49)
        at org.powermock.api.mockito.repackaged.CglibMockMaker.createMock(CglibMockMaker.java:24)
        at org.powermock.api.mockito.internal.mockmaker.PowerMockMaker.createMock(PowerMockMaker.java:45)
        at com.acme.android.myapp.services.gcm.handlers.RequestLogoutHandlerTest.setup(RequestLogoutHandlerTest.java:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        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.RunBefores.evaluate(RunBefores.java:24)
        at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:251)
        at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:188)
        at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:54)
        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.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:152)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
        at org.junit.runners.Suite.runChild(Suite.java:128)
        at org.junit.runners.Suite.runChild(Suite.java:27)
        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.runners.ParentRunner.run(ParentRunner.java:363)
        at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
        at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78)
        at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212)
        at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:6

Answer 1

我建议按照异常消息中的建议禁用Mockito的ClassCache.以下是我通过在Android Studio中添加MockitoConfiguration类来禁用Mockito ClassCache的方法.

1. 在您的单元测试目录src/test/java下,创建一个与Mockito配置包org/mockito/configuration完全相同的包目录.

2. 因此,在完整的测试目录src/test/java/org/mockito/configuration下,添加一个名为MockitoConfiguration的新类.

3. 覆盖enableClassCache()方法,如下所示.

   package org.mockito.configuration;
   
       public class MockitoConfiguration extends DefaultMockitoConfiguration {
   
       @Override
       public boolean enableClassCache() {
           return false;
       }
   }
   

4. 当您在src/java/test下运行Unit测试时,应加载MockitoConfiguration并禁用Mockito类缓存.

希望能帮助到你.

Answer 2

所以我通过添加解决了这个问题

@PowerMockIgnore({ "*.*" }) 
@PrepareForTest({ StaticClass1.class,StaticClass2.class })

这将使 Power 模拟忽略所有类。对于我的情况，PowerMock 正在类加载总线，在我的代码中，该总线实际上是由 Mockito 模拟的。一旦我在测试套件中的所有类之上添加了注释，就可以正常工作，没有任何错误。