API Import extension
If by get the extension tested you mean someone else doing it for you, unless you have an incentive (eg. budget), unlikely to happen, at least at the speed you'd like.

If it's about you or someone in your team testing: please do so!

If you are familiar with git, I would suggest you to install the extension using it, it will be easier if you have to modify something, but otherwise, you can just download the zip and put it in your extension folder.

https://github.com/eileenmcnaughton/nz.co.fuzion.csvimport.git