If you're referring to the ISO spec, it's effectively completely irrelevant.

If you're talking about ruby/spec, a comprehensive test suite is really great, but is also not what most people think about when they think of a spec, though it also may count! You could even argue that such a thing is better than a traditional spec.

Yes, I was thinking about the latter but was unsure if it counted. Yes, looking at the spec has been a helpful strategy for me to understand how something is supposed to work.