在使用Robolectric的项目中集成PowerMock遇到异常问题

我正在为依赖Android特定组件的类编写测试，使用版本：Robolectric 4.10.3、PowerMock 2.0.9。运行测试时抛出以下异常：

Failed to instantiate DeepCloner. The DeepCloner implementation must have a one-arg constructor taking a Classloader as parameter.
java.lang.RuntimeException: Failed to instantiate DeepCloner. The DeepCloner implementation must have a one-arg constructor taking a Classloader as parameter.
    at org.powermock.classloading.AbstractClassloaderExecutor.doCreateDeepCloner(AbstractClassloaderExecutor.java:108)
    at org.powermock.classloading.AbstractClassloaderExecutor.createDeepCloner(AbstractClassloaderExecutor.java:97)
    at org.powermock.classloading.AbstractClassloaderExecutor.executeWithClassLoader(AbstractClassloaderExecutor.java:52)
    at org.powermock.classloading.SingleClassloaderExecutor.execute(SingleClassloaderExecutor.java:33)
    at org.powermock.classloading.AbstractClassloaderExecutor.execute(AbstractClassloaderExecutor.java:40)
    at org.powermock.modules.junit4.rule.PowerMockStatement.evaluate(PowerMockRule.java:75)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.robolectric.RobolectricTestRunner$HelperTestRunner$1.evaluate(RobolectricTestRunner.java:589)
    at org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$2(SandboxTestRunner.java:290)
    at org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:99)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at java.base/java.lang.Thread.run(Thread.java:840)
Caused by: java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
    at org.powermock.classloading.AbstractClassloaderExecutor.doCreateDeepCloner(AbstractClassloaderExecutor.java:106)
    ... 13 more
Caused by: java.lang.ExceptionInInitializerError
    at com.thoughtworks.xstream.converters.extended.FontConverter.<init>(FontConverter.java:56)
    at com.thoughtworks.xstream.XStream.setupConverters(XStream.java:1008)
    at com.thoughtworks.xstream.XStream.<init>(XStream.java:592)
    at com.thoughtworks.xstream.XStream.<init>(XStream.java:514)
    at com.thoughtworks.xstream.XStream.<init>(XStream.java:483)
    at com.thoughtworks.xstream.XStream.<init>(XStream.java:429)
    at com.thoughtworks.xstream.XStream.<init>(XStream.java:368)
    at org.powermock.classloading.DeepCloner.<init>(DeepCloner.java:35)
    ... 19 more
Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected java.lang.String java.text.AttributedCharacterIterator$Attribute.getName() accessible: module java.base does not "opens java.text" to unnamed module @fdc3812
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)
    at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:199)
    at java.base/java.lang.reflect.Method.setAccessible(Method.java:193)
    at com.thoughtworks.xstream.converters.reflection.AbstractAttributedCharacterIteratorAttributeConverter.<clinit>(AbstractAttributedCharacterIteratorAttributeConverter.java:45)
    ... 27 more

已尝试在build.gradle的testOptions中添加以下JVM参数，但问题未解决：

all {
    jvmArgs '--add-opens=java.base/java.lang.reflect=ALL-UNNAMED',
            '--add-opens=java.base/java.lang=ALL-UNNAMED',
            '--add-opens=java.base/java.util=ALL-UNNAMED'
}

解决方案 #

从异常根因来看，是XStream尝试访问java.text.AttributedCharacterIterator$Attribute的getName()方法时，受Java模块系统限制无法获取访问权限。需要补充对应的模块开放参数：

• 补充JVM参数：修改build.gradle的testOptions配置，添加--add-opens=java.base/java.text=ALL-UNNAMED参数，完整配置如下：

testOptions {
    unitTests {
        all {
            jvmArgs '--add-opens=java.base/java.lang.reflect=ALL-UNNAMED',
                    '--add-opens=java.base/java.lang=ALL-UNNAMED',
                    '--add-opens=java.base/java.util=ALL-UNNAMED',
                    '--add-opens=java.base/java.text=ALL-UNNAMED'
        }
    }
}

• 升级PowerMock版本：若补充参数后仍有问题，可尝试升级PowerMock至2.0.10或更高版本，新版本对Java 9+模块系统的兼容性更好，可能已修复此类反射权限相关问题。

• 检查JDK版本兼容性：PowerMock 2.0.x系列对JDK 11及以上版本需要正确配置模块开放参数，确保没有遗漏必要的包路径。

内容的提问来源于stack exchange，提问作者SyntaxSage