This is more of an english language question - we have various types of tests - unit tests, A/B tests, etc...
Suppose I need to migrate code to a different language, machine, or any other different environment specification, with the definition that it reproduces the original application exactly (bugs included!). I am looking for a name for such a test.
Currently I am using functional testing, but I feel that's to general and am looking for something better. It is also somewhat misleading since the "function" is not the implemented algorithm but reproducing behavior of another application.
@Bruce suggested regression tests, which are a good option we considered, but dropped it since we (and I think most people) use those for actual changes in the original code base (in this question's setting) that may add features, fix bugs etc... Perhaps this is too nit-picky.