You can write tests for an excel spreadsheet if that is your thing. In fact Excel can be driven and automated by any .NET language. It is quite extensible. B

You can write tests for an excel spreadsheet if that is your thing. In fact Excel can be driven and automated by any .NET language. It is quite extensible. But most people don't do that because they are not developers and the word "unit test" is not part of their routine. Which is why they will not be switching to python or R any time soon and even if they do, it will still have similar issues as the Excel version. Just because you know how to use git history, diffs, etc.. to spot differences in code doesn't mean that is going to help the layperson.