For simple automated testing try the Linux (or Cygwin) 'curl' command in a shell script.
I wrote a REST client plugin called Requester for Sublime Text, github.com/kylebebak/Requester. It's inspired by HTTPie and Postman. It's very powerful and easy to use, and it's cross-platform. If you're not in love with your HTTP client it's definitely worth a try.
If you're just testing your APIs manually, we've found RestClient 2.3 or the Poster add-on for Firefox to be pretty helpful. Both of these let you build requests that GET, PUT, POST, or DELETE. You can save these requests to rerun later.
Thanks Jim! I'm currently using cURL and some bash scripts but wanted to just have the tests saved in one place (like a json or xml file that I can put in /tests/ directory of my app) and then something that allow me to re-run those tests while I develop. Will test Poster and RestClient