I have stumbled across some questions where it is hard to determine whether or not the code in the question actually works or not.

Example #1: https://codereview.stackexchange.com/questions/35616/replacing-parenthesis-in-code

Example #2: https://codereview.stackexchange.com/questions/31994/create-a-binary-search-tree-code-review-request

This has got me thinking, can we do something to encourage users to add a snippet of code that proves that there code is working as it should? Kind of like a small [unit test](http://en.wikipedia.org/wiki/Unit_testing), it does not have to be a long snippet, probably just a couple of lines for most questions.

Of course it is not possible to add such a snippet for all questions here, but I think that for many questions that ask about code that is independent from other things it would be useful.

A big advantage of providing a testing code snippet is that **it shows reviewers how their code is meant to be used**, what one or more entry-points to the code is. I believe this would help the reviewers getting a better understanding about their code in general.

So can we (or should we) do something to encourage users to include a code snippet that proves that their code works and/or how it is used?