您如何通过JUnit模拟文件读取/写入？

这是我的情况

MyHandler.java

public abstract class MyHandler {
    private String path = //..path/to/file/here
    public synchronized void writeToFile(String infoText) {
        // Some processing
        // Writing to File Here
        File file = FileUtils.getFile(filepath);
        file.createNewFile();
        // file can't be written,throw FileWriteException
        if (file.canWrite()) {
            FileUtils.writeByteArrayToFile(file,infoText.getBytes(Charsets.UTF_8));
        } else {
            throw new FileWriteException();
        }
    }
    public String readFromFile() {
        // Reading from File here
        String infoText = "";
        File file = new File(path);
        // file can't be read,throw FileReadException
        if (file.canRead()) {
            infoText = FileUtils.readFileToString(file,Charsets.UTF_8);        
        } else {
            throw FileReadException();
        }
        return infoText
    }
}

MyHandlerTest.java

@RunWith(PowerMockRunner.class)
@PrepareForTest({
    MyHandler.class
})
public class MyHandlerTest {
    private static MyHandler handler = null;
    // Some Initialization for JUnit (i.e @Before,@BeforeClass,@After,etc)
    @Test(expected = FileWriteException.class)
    public void writeFileTest() throws Exception {
       handler.writeToFile("Test Write!");
    }
    @Test(expected = FileReadException.class)
    public void readFileTest() throws Exception {
       handler.readFromFile();
    }
}

鉴于以上来源,当文件不可写(不允许写许可)时,方案是可以的,但是,当我尝试执行文件不可读(不允许读许可)的方案时.它总是读取文件,我已经尝试通过以下方式修改测试代码上的文件权限

File f = new File("..path/to/file/here");
f.setReadable(false);

但是,我做了一些阅读,setReadable()在Windows计算机上运行时总是返回false(失败).

有没有办法相对于JUnit以编程方式修改目标文件的文件许可权？

注意

Target source code to test cannot be modified,meaning
Myhandler.class is a legacy code which is not to be modified.