Well, the issue with take home tests isn't the Googling per-se, it's the hiring out of the work.
My preference for university exams was a simple, single page cheatsheet that you had to make yourself. You could write the finicky stuff that is hard to remember on it, but you couldn't fast-learn the material like you could from a book. Though I do remember writing out little programs for the weirder stuff like required coverage over concrete reinforcement bars. Which felt a bit like cheating at the time.
Next step is to go wheel of fortune style, and provide a standard cheat sheet with the finicky formulas, and then let the students at their own supplementary cheat sheet
My preference for university exams was a simple, single page cheatsheet that you had to make yourself. You could write the finicky stuff that is hard to remember on it, but you couldn't fast-learn the material like you could from a book. Though I do remember writing out little programs for the weirder stuff like required coverage over concrete reinforcement bars. Which felt a bit like cheating at the time.