一些相关信息讲解
先上一个官方的测试用例：
package org.powermock.examples.spring.mockito;
import org.easymock.TestSubject;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.annotation.Mock;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import powermock.examples.spring.FinalClass;
import powermock.examples.spring.MyBean;
import static org.easymock.EasyMock.expect;
import static org.easymock.EasyMock.replay;
import static org.junit.Assert.assertEquals;
@RunWith(PowerMockRunner.class)
@PrepareForTest(FinalClass.class)
public class SpringInjectFinalClassExampleTest {
@Mock
private FinalClass finalClass;
@TestSubject
private MyBean myBean = new MyBean();;
@Test
public void testInjectFinalClass() {
final String value = "What's up?";
expect(finalClass.sayHello()).andReturn(value);
replay(finalClass);
assertEquals(value, myBean.sayHello());
}
}
@PrepareForTest
先看官方注释：
This annotation tells PowerMock to prepare certain classes for testing. Classes needed to be defined using this annotation are typically those that needs to be byte-code manipulated. This includes final classes, classes with final, private, static or native methods that should be mocked and also classes that should be return a mock object upon instantiation.
也就是需要powermock框架将对应的final等类先进行bytecode编译之后给框架用来mock使用的类。
@Mock
官方注释：
This annotation can be placed on those fields in your test class that should be mocked. This eliminates the need to setup and tear-down mocks manually which minimizes repetitive test code and makes the test more readable. In order for PowerMock to control the life-cycle of the mocks you must supply the PowerMockListener annotation to the class-level of the test case. For example:
“放在应该被mock的类上面”。当然如果一个类之中的方法过多，也可以直接指定对应要mock的方法。
注意 mock 和 spy的不同用法，mock之中在测试代码里面需要将用到的所有方法打桩，也就是其只是一个壳。但是spy是产生真实的对象，对其中的某些行为进行更改。
expect
这个是Easymock之中的，一般和andReturn() 一起：
expect(finalClass.sayHello()).andReturn(value);
对expect()之中的行为进行打桩，并且返回后面的andReturn()中内容。如果@Mock标示的对象没有对应的expect()作为打桩，那么调用方法的时候就会直接返回null（框架也不知道要mock什么出来）
replay
是Easymock之中的，用来将对应的mock的调用重放，除非对一个方法多次调用，需要多个mock的时候之外一般可以不用。
参考：https://www.cnblogs.com/ld-mars/p/12082200.html
当代码里涉及到同一个接口方法多次调用时，如果仅仅是在单元测试里EasyMock方法，而没有replay()时，在单元测试运行的时候，是无法对接口方法进行Mock的。
EasyMock.replay()是将Mock的行为按照Mock的步骤重发一遍，在单元测试运行的时候，就能够正确的执行了。
@TestSubject
Easymock中。标示要测试的类，powermock会将mock的类注入其中。
invokeMethod
用来测试private的method，或者是内部类的method
/**
* Invoke a private or inner class method. This might be useful to test
* private methods.
*/
public static synchronized <T> T invokeMethod(Object instance, String methodToExecute, Object... arguments)
throws Exception {
return WhiteboxImpl.invokeMethod(instance, methodToExecute, arguments);
}
expectNew
也包括一系列的相关方法，比如createMockAndExpectNew等等。
/**
* Convenience method for createMock followed by expectNew.
*
* @param type The class that should be mocked.
* @param arguments The constructor arguments.
* @return A mock object of the same type as the mock.
* @throws Exception
*/
public static synchronized <T> T createMockAndExpectNew(Class<T> type, Object... arguments) throws Exception {
T mock = createMock(type);
expectNew(type, arguments).andReturn(mock);
return mock;
}
/**
* Allows specifying expectations on new invocations. For example you might
* want to throw an exception or return a mock. Note that you must replay
* the class when using this method since this behavior is part of the class
* mock.
*/
public static synchronized <T> IExpectationSetters<T> expectNew(Class<T> type, Object... arguments)
throws Exception {
return doExpectNew(type, new DefaultMockStrategy(), null, arguments);
}
用在被测试方法之中有new相关的调用，比如：
@Override
public boolean createPerson(String firstName, String lastName) {
BusinessMessages messages = new BusinessMessages();
Person person = null;
try {
person = new Person(firstName, lastName);
} catch (IllegalArgumentException e) {
throw new SampleServiceException(e.getMessage(), e);
里面对于messages是new BusinessMessages，所以要：
// Mock the creation of BusinessMessages
BusinessMessages businessMessagesMock = createMockAndExpectNew(BusinessMessages.class);
而不是单纯的直接Mock一个对象插进去（因为被测试方法之中是有自己的new创建对象而非直接使用类已有对象）
例子
内部组件的注入
用setInternalState()
/**
* Set the value of a field using reflection. This method will traverse the
* super class hierarchy until the first field assignable to the
* <tt>value</tt> type is found. The <tt>value</tt> (or
* <tt>additionaValues</tt> if present) will then be assigned to this field.
*
* @param object
* the object to modify
* @param value
* the new value of the field
* @param additionalValues
* Additional values to set on the object
*/
public static void setInternalState(Object object, Object value, Object... additionalValues) {
WhiteboxImpl.setInternalState(object, value, additionalValues);
}
举例：将bundleContextMock 注入到 tested之中：
setInternalState(tested, bundleContextMock);
void类型的取值和验证
函数的返回值是void, 没法expect...andReturn，用下面的方式：
// TODO Expect the call to serviceRegistrationMock.unregister()
// 此处的 serviceRegistrationMock.unregister() 返回void
serviceRegistrationMock.unregister();
PowerMock.expectLastCall().times(1);
抛出和检验异常
被测试方法：
@Override
public void unregisterService(long id) {
final ServiceRegistration registration = serviceRegistrations.remove(id);
if (registration == null) {
throw new IllegalStateException("Registration with id " + id + " has already been removed or has never been registered");
}
registration.unregister();
}
如何测试：用fail()
// TODO Expect the call to serviceRegistrationMock.unregister() and throw an IllegalStateException
try{
tested.unregisterService(id);
fail("Here should throw Exception....");
}catch (IllegalStateException e){
assertEquals("Registration with id " + id + " has already been removed or has never been registered", e.getMessage());
}
在运行时候发生org.objenesis.ObjenesisException: java.lang.reflect.InvocationTargetException
详细报错是：可以看到主要是因为java.lang.reflect.InvocationTargetException.
解决方案：可以看到其是“调用部分出现异常”，查询之后发现是因为jdk版本不是jdk8 导致的。在run设置之中更改其为jdk8即可。
org.objenesis.ObjenesisException: java.lang.reflect.InvocationTargetException
at org.objenesis.instantiator.sun.SunReflectionFactoryHelper.newConstructorForSerialization(SunReflectionFactoryHelper.java:54)
at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.<init>(SunReflectionFactoryInstantiator.java:38)
at org.objenesis.strategy.StdInstantiatorStrategy.newInstantiatorOf(StdInstantiatorStrategy.java:68)
at org.objenesis.ObjenesisBase.getInstantiatorOf(ObjenesisBase.java:91)
at org.powermock.reflect.internal.WhiteboxImpl.newInstance(WhiteboxImpl.java:259)
at org.powermock.reflect.Whitebox.newInstance(Whitebox.java:139)
at org.powermock.tests.utils.impl.AbstractTestSuiteChunkerImpl.getPowerMockTestListenersLoadedByASpecificClassLoader(AbstractTestSuiteChunkerImpl.java:95)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.createDelegatorFromClassloader(JUnit4TestSuiteChunkerImpl.java:174)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.createDelegatorFromClassloader(JUnit4TestSuiteChunkerImpl.java:48)
at org.powermock.tests.utils.impl.AbstractTestSuiteChunkerImpl.createTestDelegators(AbstractTestSuiteChunkerImpl.java:108)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.<init>(JUnit4TestSuiteChunkerImpl.java:71)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.<init>(AbstractCommonPowerMockRunner.java:36)
at org.powermock.modules.junit4.PowerMockRunner.<init>(PowerMockRunner.java:34)
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.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
at org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:36)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:50)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.objenesis.instantiator.sun.SunReflectionFactoryHelper.newConstructorForSerialization(SunReflectionFactoryHelper.java:44)
... 28 more
Caused by: java.lang.IllegalAccessError: class jdk.internal.reflect.ConstructorAccessorImpl loaded by org.powermock.core.classloader.MockClassLoader @233c0b17 cannot access jdk/internal/reflect superclass jdk.internal.reflect.MagicAccessorImpl
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1012)
at org.powermock.core.classloader.MockClassLoader.loadUnmockedClass(MockClassLoader.java:262)
at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:206)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass1(DeferSupportingClassLoader.java:89)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:79)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1012)
at org.powermock.core.classloader.MockClassLoader.loadUnmockedClass(MockClassLoader.java:262)
at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:206)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass1(DeferSupportingClassLoader.java:89)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:79)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.System$2.defineClass(System.java:2303)
at java.base/jdk.internal.reflect.ClassDefiner.defineClass(ClassDefiner.java:66)
at java.base/jdk.internal.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:401)
at java.base/jdk.internal.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:395)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:318)
at java.base/jdk.internal.reflect.MethodAccessorGenerator.generate(MethodAccessorGenerator.java:394)
at java.base/jdk.internal.reflect.MethodAccessorGenerator.generateSerializationConstructor(MethodAccessorGenerator.java:112)
at java.base/jdk.internal.reflect.ReflectionFactory.generateConstructor(ReflectionFactory.java:463)
at java.base/jdk.internal.reflect.ReflectionFactory.newConstructorForSerialization(ReflectionFactory.java:376)
at jdk.unsupported/sun.reflect.ReflectionFactory.newConstructorForSerialization(ReflectionFactory.java:100)
... 33 more
Powermock在jdk11之中不匹配
主要是如下的报错，显示 org.powermock.core.classloader.MockClassLoader 无法访问jdk/internal/reflect superclass jdk.internal.reflect.MagicAccessorImpl
解决方法：添加@PowerMockIgnore("jdk.internal.reflect.*")
为什么可以解决：
没找到 jdk11之中的解释，但是找到了 jdk9 之中对于这个的官方maintainer回答，就是 powermock 本身对于新版本的 jdk支持不好，导致其自定义的类加载器中找不到某些类：
https://github.com/powermock/powermock/issues/864
具体报错如下：
org.objenesis.ObjenesisException: java.lang.reflect.InvocationTargetException
at org.objenesis.instantiator.sun.SunReflectionFactoryHelper.newConstructorForSerialization(SunReflectionFactoryHelper.java:54)
at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.<init>(SunReflectionFactoryInstantiator.java:38)
at org.objenesis.strategy.StdInstantiatorStrategy.newInstantiatorOf(StdInstantiatorStrategy.java:68)
at org.objenesis.ObjenesisBase.getInstantiatorOf(ObjenesisBase.java:91)
at org.powermock.reflect.internal.WhiteboxImpl.newInstance(WhiteboxImpl.java:259)
at org.powermock.reflect.Whitebox.newInstance(Whitebox.java:139)
at org.powermock.tests.utils.impl.AbstractTestSuiteChunkerImpl.getPowerMockTestListenersLoadedByASpecificClassLoader(AbstractTestSuiteChunkerImpl.java:95)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.createDelegatorFromClassloader(JUnit4TestSuiteChunkerImpl.java:174)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.createDelegatorFromClassloader(JUnit4TestSuiteChunkerImpl.java:48)
at org.powermock.tests.utils.impl.AbstractTestSuiteChunkerImpl.createTestDelegators(AbstractTestSuiteChunkerImpl.java:108)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.<init>(JUnit4TestSuiteChunkerImpl.java:71)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.<init>(AbstractCommonPowerMockRunner.java:36)
at org.powermock.modules.junit4.PowerMockRunner.<init>(PowerMockRunner.java:34)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
at org.junit.internal.requests.ClassRequest.buildRunner(ClassRequest.java:33)
at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:28)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:50)
at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.objenesis.instantiator.sun.SunReflectionFactoryHelper.newConstructorForSerialization(SunReflectionFactoryHelper.java:44)
... 24 more
Caused by: java.lang.IllegalAccessError: class jdk.internal.reflect.ConstructorAccessorImpl loaded by org.powermock.core.classloader.MockClassLoader @6043cd28 cannot access jdk/internal/reflect superclass jdk.internal.reflect.MagicAccessorImpl
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
at org.powermock.core.classloader.MockClassLoader.loadUnmockedClass(MockClassLoader.java:262)
at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:206)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass1(DeferSupportingClassLoader.java:89)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:79)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
at java.base/java.lang.ClassLoader.defineClass1(Native Method)
at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
at org.powermock.core.classloader.MockClassLoader.loadUnmockedClass(MockClassLoader.java:262)
at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:206)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass1(DeferSupportingClassLoader.java:89)
at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:79)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
at java.base/jdk.internal.misc.Unsafe.defineClass0(Native Method)
at java.base/jdk.internal.misc.Unsafe.defineClass(Unsafe.java:1192)
at java.base/jdk.internal.reflect.ClassDefiner.defineClass(ClassDefiner.java:63)
at java.base/jdk.internal.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:400)
at java.base/jdk.internal.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:394)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/jdk.internal.reflect.MethodAccessorGenerator.generate(MethodAccessorGenerator.java:393)
at java.base/jdk.internal.reflect.MethodAccessorGenerator.generateSerializationConstructor(MethodAccessorGenerator.java:112)
at java.base/jdk.internal.reflect.ReflectionFactory.generateConstructor(ReflectionFactory.java:514)
at java.base/jdk.internal.reflect.ReflectionFactory.newConstructorForSerialization(ReflectionFactory.java:427)
at jdk.unsupported/sun.reflect.ReflectionFactory.newConstructorForSerialization(ReflectionFactory.java:103)
... 29 more
