Could there possibly be a massive extensive test

But who would be incentivized to provide that test?

The employer? He doesn't have to -- he has plenty of degree-holding candidate to choose from, and doesn't need even more candidates to choose from, nor the costs and time that would be required to add testing to their hiring process.

The university? Why would they? They get paid by people taking classes, so why would they provide degree-equivalents to people who did not attend their university, thus providing an incentive for people to not pay them for classes?

could there be a way to filter out all of the 'fluff'

Part of college -- or at least, a four-year bachelor's degree -- is that "fluff". If you want just the meat-and-potatoes skills, you're talking about a trade school or an associate's degree -- and there's nothing wrong with trade schools and associates degrees. A university education, on the other hand, is designed to specialize in a particular set of skills, while also providing a broader education in order to avoid being knowledgeable about one and only one thing. For some careers, that's valuable -- if you're part of a creative team, for instance, having a variety of backgrounds, rather than a bunch of people with the same narrow skill set, can be important. This is why minors and double-majors are increasingly common -- people want to show that they're aren't just knowledgeable in one narrow area, but rather have a valuable combination of skills and knowledge that distinguishes them on the job market.

But if you don't want all that, plenty of community colleges and technical and vocational schools offer a two-year associates degree that doesn't have all the elective requirements of a four-year program.