How can I test the 'catch' portion of code in a try-catch, using Mockito, when the 'try' is 'Thread.Sleep()?

I’m using mockito to write test, but I’m really struggling with how to test this specific bit of code:

public void myMethod() {
try {
Thread.sleep(400);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}

A lot of examples online use the example of forcing whatever is in the try to throw an error – but everything I’ve looked at yells ‘don’t mock a Thread’

Is there a way I can force the code to be interrupted using Thread.interrupt() or similar?

I did start to try and use a spy:

Thread threadSpy = spy(new Thread());
threadSpy.interrupt();
assertThatExceptionOfType(RuntimeException.class);

but I can see that this isn’t actually causing the thread in myMethod to interrupt, so isn’t actually testing that bit of code.

>Solution :

Here is the test

public class AppTest {
    @SneakyThrows
    @Test
    void test() {
        AtomicReference<Throwable> reference = new AtomicReference<>();
        Thread thread = new Thread(() -> {
            try {
                myMethod();
            } catch (Throwable t) {
                reference.set(t);
            }
        });

        thread.start();
        thread.interrupt();
        thread.join();
        assertNotNull(reference.get());
    }

    public void myMethod() {
        try {
            Thread.sleep(400);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }
}

Make sure that sleep value is sufficiently large.