Unit testing 在多个文件上使用Power Mock运行Robolectric测试时发生ClassCastException异常

因此，我根据参考指南建立了powermock。使用一个测试类，一切似乎都运行得很好。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

从下面的stacktrace中可以看到，我试图模拟一个otto总线实例。在第一个测试类上，它似乎进行了适当的模拟，但在第二个类上，我得到了这个类强制转换异常

在stacktrace上，我得到了禁用Objenisis缓存的建议，但我不确定如何做到这一点，也不确定这是否是根本原因，因为我正在使用classloading xstream:1.6.2，正如上面附加的Robolectric Wiki链接所示

问题是，如果我运行一个JUnit测试类，我的设置工作得很好，但是一旦我尝试运行包中的所有测试，只有第一个测试可以工作，后续的测试将得到类强制转换异常

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

---

所以我通过添加

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

---

这将使Power mock忽略所有类。在我的例子中，PowerMock正在类加载总线，而在我的代码中，总线实际上是由Mockito模拟的

我建议按照异常消息中的建议禁用Mockito的类缓存 . 下面是我如何通过在androidstudio中添加MockitoConfiguration类来禁用Mockito类缓存的

在单元测试目录src/test/java下，创建一个与Mockito配置包org/Mockito/configuration完全相同的包目录

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

覆盖enableClassCache（）方法，如下所示

package org.mockito.configuration;

    public class MockitoConfiguration extends DefaultMockitoConfiguration {

    @Override
    public boolean enableClassCache() {
        return false;
    }
}

当您在src/java/test下运行单元测试时，应该加载Mockito配置并禁用Mockito类缓存

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希望能有所帮助。

在某些情况下，这可能会起作用，但如果您有一套混合使用PowerMockito和Mockito的测试，我发现这样做会有问题。在使用PowerMockito的测试中，使用MockitoConfiguration类和@PowerMockIgnore（{“org.mockito.*}）组合答案对我来说很有用。谢谢