带有Mockito的PowerMock不'；t为构造函数调用创建模拟

我试图在每次创建FileOutputStream的任何构造函数时使用PowerMock和mockito来创建mock，但它似乎返回一个真实的实例，而不是模拟的实例

我的测试班：

@RunWith(PowerMockRunner.class)
@PrepareForTest({FileOutputStream.class,FilesHelper.class})
public class FilesHelperTest {


@Test
public void createFileFromInputStream_validate_null_progress_subject_doesnt_throws_null_pointer() throws Exception {
    FileOutputStream fileOutputStream = Mockito.mock(FileOutputStream.class);
    PowerMockito.whenNew(FileOutputStream.class).withAnyArguments().thenReturn(fileOutputStream);
    File file = Mockito.mock(File.class);
    BufferedSource bufferedSource = Mockito.mock(BufferedSource.class);
    Mockito.doReturn(true).when(file).exists();
    Mockito.when(bufferedSource.read(Mockito.any(),Mockito.anyLong())).thenReturn(15L,-1L);
    FilesHelper.createFileFromInputStream(file,bufferedSource,8,null);
 }
}

我的班级在测试中-

public class FilesHelper {

/**
 * Creates a file out of an input stream wrapped by Okio's {@link BufferedSource}.
 * @param file a file to save the input to
 * @param bufferedSource the source input.
 * @param maxSize the maximum amount of bytes can be loaded to memory
 * @param progressUpdatePublisher an optional update publisher which notifies the writing progress
 * @return a {@link com.bonimoo.wominstaller.data.entities.BaseDownloadStatusDTO.Done} status with all the necessary information.
 * @throws IOException in case of errors while writing
 * @throws IllegalStateException when the file doesn't exists and cannot be created
 */
public static BaseDownloadStatusDTO.Done createFileFromInputStream(File file, BufferedSource bufferedSource, int maxSize, @Nullable PublishSubject<BaseDownloadStatusDTO> progressUpdatePublisher) throws IOException, IllegalStateException {
    if (!file.exists()) {
        Throwable cause = null;
        boolean created = false;
        try {
            created = file.createNewFile();
        } catch (IOException e) {
            cause = e;
        }
        if (!created) {
            throw new IllegalStateException("FilesHelper cannot create new file",cause);
        }
    }
    if (progressUpdatePublisher != null) {
        progressUpdatePublisher.onNext(new BaseDownloadStatusDTO.Started(file.getAbsolutePath()));
    }
    BufferedSink sink = Okio.buffer(Okio.sink(file));
    Buffer buffer = new Buffer();
    long counter = 0L;
    try {
        for (long readCount = bufferedSource.read(buffer, maxSize); readCount > -1 || bufferedSource.exhausted(); readCount = bufferedSource.read(buffer, maxSize)) {
            sink.writeAll(buffer);
            counter += readCount;
            if (progressUpdatePublisher != null) {
                progressUpdatePublisher.onNext(new BaseDownloadStatusDTO.Progress(counter,file.getAbsolutePath(),readCount));
            }
        }
    } finally {
        sink.flush();
        sink.close();
        buffer.close();
        bufferedSource.close();
    }
    return new BaseDownloadStatusDTO.Done(file);
 }
}

公共类文件帮助器{
/**
*从Okio的{@link BufferedSource}包装的输入流中创建一个文件。
*@param file保存输入的文件
*@param bufferedSource源输入。
*@param maxSize可加载到内存的最大字节数
*@param progressUpdatePublisher一个可选的更新发布程序，用于通知写入进度
*@return a{@link com.bonimoo.womsinstaller.data.entities.BaseDownloadStatusDTO.Done}状态以及所有必要的信息。
*@在写入时出错时引发IOException
*@在文件不存在且无法创建时引发IllegalStateException
*/
public static BaseDownloadStatusDTO.Done createFileFromInputStream（文件文件，BufferedSource BufferedSource，int maxSize，@Nullable PublishSubject progressUpdatePublisher）引发IOException，IllegalStateException{
如果（！file.exists（））{
可丢弃原因=空；
布尔值=假；
试一试{
created=file.createNewFile（）；
}捕获（IOE异常）{
原因=e；
}
如果（！已创建）{
抛出新的非法状态异常（“FileHelper无法创建新文件”，原因）；
}
}
if（progressUpdatePublisher！=null）{
progressUpdatePublisher.onNext（新的BaseDownloadStatusDTO.Started（file.getAbsolutePath（））；
}
BufferedSink sink=Okio.buffer（Okio.sink（文件））；
缓冲区=新缓冲区（）；
长计数器=0L；
试一试{
for（long readCount=bufferedSource.read（buffer，maxSize）；readCount>-1 | | | bufferedSource.defined（）；readCount=bufferedSource.read（buffer，maxSize））{
sink.writeAll（缓冲区）；
计数器+=读取计数；
if（progressUpdatePublisher！=null）{
progressUpdatePublisher.onNext（新的BaseDownloadStatusDTO.Progress（计数器，file.getAbsolutePath（），readCount））；
}
}
}最后{
下沉。冲洗（）；
sink.close（）；
buffer.close（）；
bufferedSource.close（）；
}
返回新的BaseDownloadStatusDTO.Done（文件）；
}
}

因此，当我创建类时，我仍然会得到由实际构造函数调用引发的null指针异常

java.lang.NullPointerException
    at java.io.FileOutputStream.<init>(FileOutputStream.java:203)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:162)
    at okio.Okio.sink(Okio.java:181)
    at com.bonimoo.wominstaller.data.helpers.FilesHelper.createFileFromInputStream(FilesHelper.java:49)
    at com.bonimoo.wominstaller.data.helpers.FilesHelperTest.createFileFromInputStream_validate_null_progress_subject_doesnt_throws_null_pointer(FilesHelperTest.java:36)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:68)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:326)
    at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:89)
    at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:97)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:310)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:131)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.access$100(PowerMockJUnit47RunnerDelegateImpl.java:59)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner$TestExecutorStatement.evaluate(PowerMockJUnit47RunnerDelegateImpl.java:147)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.evaluateStatement(PowerMockJUnit47RunnerDelegateImpl.java:107)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:298)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:218)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:160)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:134)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:136)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:117)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:57)
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

java.lang.NullPointerException
位于java.io.FileOutputStream。（FileOutputStream.java:203）
位于java.io.FileOutputStream。（FileOutputStream.java:162）
在okio.okio.sink（okio.java:181）
位于com.bonimoo.womsInstaller.data.helpers.fileHelper.createFileFromInputStream（fileHelper.java:49）
在com.bonimoo.womsInstaller.data.helpers.filehelpertest.createFileFromInputStream\u validate\u null\u progress\u subject\u doesnt\u throws\u null\u指针（FilesHelperTest.java:36）
在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处
位于sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）
在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）中
位于java.lang.reflect.Method.invoke（Method.java:498）
位于org.junit.internal.runners.TestMethod.invoke（TestMethod.java:68）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod（PowerMockJUnit44RunnerDelegateImpl.java:326）
位于org.junit.internal.runners.MethodRoadie$2.run（MethodRoadie.java:89）
位于org.junit.internal.runners.MethodRoadie.runbeforesthentestthenuter（MethodRoadie.java:97）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest（PowerMockJUnit44RunnerDelegateImpl.java:310）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper（PowerMockJUnit47RunnerDelegateImpl.java:131）
在org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.access$100（PowerMockJUnit47RunnerDelegateImpl.java:59）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner$TestExecutorStatement.evaluate（PowerMockJUnit47RunnerDelegateImpl.java:147）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.evaluateStatement（PowerMockJUnit47RunnerDelegateImpl.java:107）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest（PowerMockJUnit47RunnerDelegateImpl.java:82）
位于org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runbeforesthenTesttheAfter（PowerMockJUnit44RunnerDelegateImpl.java:298）
位于org.junit.internal.runners.MethodRoadie.runTest（MethodRoadie.java:87）
位于org.junit.internal.runners.MethodRoadie.run（MethodRoadie.java:50）
位于org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateinpl.invokeTestMethod（powermockjunit44runnerdelegateinpl.java:218）
位于org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateinpl.runMethods（powermockjunit44runnerdelegateinpl.java:160）
位于org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateinpl$1.run（powermockjunit44runnerdelegateinpl.java:134）
位于org.junit.internal.runners.ClassRoadie.runUnprotected（ClassRoadie.java:34）
位于org.junit.internal.runners.ClassRoadie.runProtected（ClassRoadie.java:44）
位于org.powermock.modules.junit4.internal.impl.powermockjunit44runnerdelegateinpl.run（powermockjunit44runnerdelegateinpl.java:136）
位于org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run（JUnit4TestSuiteChunkerImpl.java:117）
在org.powermock.modules.jun