Reverse refactoring tool

Kind of a strange question: is there a tool that can reverse refactor (defactor?) source code?

I'm writing a paper on the difference of testability of refactored and non-refactored code. For this I need not too complex (preferably) python packages in refactored and non-refactored implementation. A tool that can automatically reverse refactor code without breaking it (that is, the two versions should generate the same output for the same input) would greatly help me, since refactored code seems to be easier to find.

I did not find such tool yet, if someone knows one I'd appreciate the help.