PowerMock: How to unmock a method?

Question

I have a static method that is mocked using PowerMock to throw an exception. (It deletes files.) Unfortunately, during my @After (after-each-test) method, I need to call this method without the mocks. How can I umock a method?

I don't see an equivalent to Mockito.reset(). [ Ref: mockito : how to unmock a method? ]

Example:

@RunWith(PowerMockRunner.class)
@PrepareForTest(PathUtils.class)  // Important: This class has a static method we want to mock.
public class CleaningServiceImplTest2 extends TestBase {

    public static final File testDirPath = new File(CleaningServiceImplTest2.class.getSimpleName());

    @BeforeClass
    public static void beforeAllTests() throws PathException {
        recursiveDeleteDirectory(testDirPath);
    }

    @AfterClass
    public static void afterAllTests() throws PathException {
        recursiveDeleteDirectory(testDirPath);
    }

    private File randomParentDirPath;
    private CleaningServiceImpl classUnderTest;

    @Before
    public void beforeEachTest() {
        randomParentDirPath = new File(testDirPath, UUID.randomUUID().toString()).getAbsoluteFile();
        classUnderTest = new CleaningServiceImpl(randomParentDirPath);
    }

    @After
    public void afterEachTest() throws PathException {
        recursiveDeleteDirectory(randomParentDirPath);
    }

    public static void recursiveDeleteDirectory(File dirPath) throws PathException {
        // calls PathUtils.removeFile(...)
    }

    @Test
    public void run_FailWhenCannotRemoveFile() throws IOException {
        // We only want to mock one method.  Use spy() and not mockStatic().
        PowerMockito.spy(PathUtils.class);

        // These two statements are tightly bound.
        PowerMockito.doThrow(new PathException(PathException.PathExceptionReason.UNKNOWN, randomParentDirPath, null, "message"))
            .when(PathUtils.class);
        PathUtils.removeFile(Mockito.any(File.class));

        classUnderTest.run();
    }
}

Answer 1

This took me a while to figure out, so I am answering my own question.

AFAIK, you need to "undo" each mock. Mockito.reset() will not work with Class<?> references. At the end of the test method, add:

// Undo the mock above because we need to call PathUtils.removeFile() within @After.
PowerMockito.doCallRealMethod().when(PathUtils.class);
PathUtils.removeFile(Mockito.any(File.class));