Just tweeted an article published by Sauce Labs on “Reducing False Positives in Automated Testing” that takes the form of a Q&A about automation. I mostly agree with the article but there is one answers that bothers me :

Should the test automation framework be written in the same language the application is being written or developed in?

A: Yes. Creating the automation framework in the same language of application will help the development team in testing specified areas whenever there is any code change or defect fix.[…]

I would replace the “yes” by “it depends”. I also see value in using another langage to automate functional tests. Specially when you have a dedicated QA/tester team. Here are a couple of reasons:

• if your company is producing different products in different langages, then it could be difficult for your QA team to keep up with those different langages for their automation. So using a single langage for the tests would ease QA life. That would also allow QA to share libraries/tools among different tests for different SUT.
• hiring skilled QA is not easy. Finding people with good functional understanding/curiosity of the SUT *and* a good technical knowledge can be difficult. Asking them to code in a langage like Python/Ruby rather than coding in C, C#, Java etc. could be make it easier to achieve
• using a different langage than the SUT is also a good way to force QA (or dev if they code tests) to take a new perspective on the SUT. If you test your Java product in Java, you might swim in the “integration tests” water and even when you try to black-box test your application, you might end up interacting with the SUT in a gray-box way.

In the end it really depends on your organisation, culture, people etc. but it is worth having a debate on that point. You might want to take a look at this other article on the same subject: Your automated acceptance tests needn’t be written in the same language as your system being tested