Just making sure I understand what you're asking. Looking at the implementation of ```Filter.ALL``` it overrides the ```apply``` method with an empty implementation. That is

```
        @Override
        public void apply(Object child) throws NoTestsRemainException {
            // do nothing
        }
```

So as far as I can tell, it doesn't matter what the implementation of Filterable is for the child, as it'll never be invoked by ```Filter.ALL```. So the test you described, would pass regardless of whether I implement filter on ```IgnoredClassRunner``` or not.

Let me know if I'm missing something. Thanks