Java 如何从模拟路径加载模拟文件

我正在尝试为一个函数编写单元测试，该函数尝试从磁盘获取文件并对其进行流式传输：

public InputStream downloadFile(String folderName, String fileName) throws FileNotFoundException {
    File name = Paths.get("/tmp/portal", folderName, fileName).toFile();

    return new FileInputStream(name);
  }

我的试用码

 @InjectMock MyService myService;
   
    @TempDir
        Path mockDirectory;
     @Test
        void downloadFile() throws IOException {
     Path mockFile = mockDirectory.resolve("testFile");
            Files.createFile(mockFile);
     String folderName= mockFile.subpath(5, 6).toString();
     String filename= mockFile.getFileName().toString();
        InputStream inputStreamResult = myService.downloadFile(folderName, filename);
    }

错误是

文件：testFile不存在

---

您收到一个错误

testFile not exists

，因为

downloadFile

方法中有一个硬编码路径

“/tmp/portal”

下面是下载该文件的单元测试示例：

interface Service {
    Cipher getDecryptCipher();
}

class FileDownloader {

    private final Service service;

    public FileDownloader(Service service) {
        this.service = service;
    }

    public InputStream downloadFile(String folderName, String fileName) throws FileNotFoundException {
        File file = Paths.get(folderName, fileName).toFile();
        return new CipherInputStream(new FileInputStream(file), service.getDecryptCipher());
    }
}

@ExtendWith(MockitoExtension.class)
class FileDownloaderTest {

    @TempDir
    Path directory;
    @Mock
    Service service;
    @Mock
    Cipher cipher;
    @InjectMocks
    FileDownloader fileDownloader;

    @Test
    void fileContentIsDownloaded() throws IOException {

        String testFileName = "testFile";
        String testFileContent = "test text";

        Path testFile = directory.resolve(testFileName);
        Files.createFile(testFile);
        Files.write(testFile, testFileContent.getBytes());
        when(service.getDecryptCipher()).thenReturn(cipher);

        InputStream actualInputStream = fileDownloader.downloadFile(directory.toString(), testFileName);

        CipherInputStream expectedInputStream = new CipherInputStream(new ByteArrayInputStream(testFileContent.getBytes()), cipher);
        assertThat(actualInputStream).hasSameContentAs(expectedInputStream);
    }
}

---

感谢我写下返回值是这样的，new

CipherInputStream（newFileInputStream（file），service.getDecryptCipher（））由于您的执行，我收到一个错误，文件无法删除，如何模拟密码？你能相应地更改代码吗？然后我将接受答案：）@Catalina我已使用模拟密码更新了答案。我收到以下错误：
警告：关闭java.io时出错。BufferedReader@706507f8java.lang.IllegalStateException:密码未初始化
也有此错误：
ed:java.nio.file.FileSystemException:C:\Users\catalina\AppData\Local\Temp\junit10056578990060702957\testFile:该进程无法访问该文件，因为它正被另一进程使用。
请帮助我：(