最终类上的PowerMock UnfinishedStubbingException错误

Question

试图让Mockito和PowerMock正常运行，但在尝试运行以下代码时，我得到了UnfinishedStubbingException:

@RunWith(PowerMockRunner.class)
@PrepareForTest(FileIOHelper.class)
public class FileIOHelperTest {

    @Test
    public void testIOExceptionOnWrite() {
        PowerMockito.mockStatic(FileIOHelper.class);
        PowerMockito.doThrow(new IOException()).when(FileIOHelper.class);
        PowerMockito.verifyStatic();
        FileIOHelper.write(Mockito.anyString(), Mockito.anyString());
    }

    @After
    public void validate() {
        Mockito.validateMockitoUsage();
    }

}

而这个IO类

public final class FileIOHelper {

    public static void write(final String file, String message, final boolean appendNewLine) {
        if(checkArgs(file, message)) {
            final Path path = Paths.get(file);
            StandardOpenOption mode = StandardOpenOption.APPEND;
            if(Files.notExists(path)) {
                mode = StandardOpenOption.CREATE_NEW;
            }
            if(appendNewLine) {
                message += System.getProperty("line.separator");
            }
            try {
                Files.write(path, message.getBytes(), mode);
            } catch(IOException e) {
                handleException(e, "Problem writing to " + file);
            }
        }
    }

    private static boolean checkArgs(final String... args) {
        if(args != null && args.length > 0) {
            for(final String arg : args) {
                if(arg == null || arg.isEmpty()) {
                    return false;
                }
            }
        }

        return true;
    }

    private static void handleException(final IOException e, final String errorMsg) {
        handleException(e, errorMsg, true);
    }

    private static void handleException(final IOException e, final String errorMsg, final boolean printStace) {
        checkArgs(errorMsg);

        System.err.println(errorMsg);
        System.err.println(e.getMessage());

        if(printStace) {
            e.printStackTrace();
        }
    }

}

我想要做的是以某种方式触发IOException，以便可以测试HandleException。为什么有人会问？我在看我的Jacoco报告，我看到了这个：

null

org.mockito.exceptions.misusing.UnfinishedStubbingException: 
Unfinished stubbing detected here:
-> at FileIOHelperTest.testIOExceptionOnWrite(FileIOHelperTest.java:8) // doThrow line

E.g. thenReturn() may be missing.
Examples of correct stubbing:
    when(mock.isOk()).thenReturn(true);
    when(mock.isOk()).thenThrow(exception);
    doThrow(exception).when(mock).someVoidMethod();
Hints:
 1. missing thenReturn()
 2. you are trying to stub a final method, you naughty developer!
 3: you are stubbing the behaviour of another mock inside before 'thenReturn' instruction if completed

Answer 1

我的建议：忘记使用PowerMock。

如果您必须模拟静态方法，那么围绕它构建您自己的小包装类。然后，为了进行测试，您的包装器可以返回您控制的内容；和生产用途；包装器只调用静态方法。

PowerMock看起来是许多问题的解决方案；但它迟早会成为更多问题的原因。它打破了覆盖范围，使底层JVM更难更改，等等。