Keyword being "a". Best solution? Most easily maintained? I don't know about that.
> In practice, it turns out these tests are good enough to synthesize methods from a lot of production grade Ruby on Rails web apps
Yeah, for some very basic stuff, you might have invented an overly complicated way of building boilerplate code.
Your argument is that the tests being incomplete make it tractable and this is an "advantage" somehow - I don't think this is such an advantage. The majority of "useful" tests either are stand-ins for what the language should have given you anyways (proper type checking), or they find and fix known bugs, e.g. the intersection of three features.
They rarely properly specify functionality, usually the best way to do this is writing the actual code. At which point, to properly specify your functionality in "test" form, you must write the actual code as a test. This doesn't provide much benefit, outside of having perhaps automated one side of a counterproductive process. You do save some programmer time, but writing the code is and was never the hard part...