[nicoburns]

Yes, but the fact that someone had to do this makes it clear that the spec isn't complete. A complete spec would state the algorithm unambiguously. You might still need to fix bugs based on tests, but you shouldn't need to be working about behaviour because it's unspecified.

[asiachick]

Not my experience at all. It doesn't matter how well written a spec is. No tests = no conformance. End of story. Most people can't hold an entire spec in their head or think through all the ramifications of the edge cases. Even the spec writers. I work on several specs. I work with people who work on specs. They're all mortal. No test = divergence. Always and without fail.