How do you test the APIs you build?
For the project I'm currently working on, I had to do a complete rewrite of an API (and a quite old one). To easily ensure the compatibility between the new API and the old one I used Behat to write "tests" that can be executed against both versions.
I used Behat 3 with a slightly customized version of the Behat/WebApiExtension [1]. The main enhancement I did to this extension was a - quick'n'dirty - integration of the coduo/php-matcher [2] library. It allows me to write cleaner/smaller scenarii and test only the parts of the response that I'm interested in.
So, what tools/methods do you use to test your APIs?
[1]
https://github.com/Behat/WebApiExtension[2]
https://github.com/coduo/php-matcher