Take homes are probably the best way to test actual coding abilities. I had a pretty good online coding test done by Microsoft actually, it was 2 hours of building an API; no trick questions, no big-o, just write a bunch of code. It wasn't easy but it felt as if they're actually testing what I do for a living. I passed it and it didn't go to the follow up - which would have probably been a shitty whiteboard interview but I'm not sure. Now that I think about it maybe I should have gone to that interview ...