Playgrounds for Objective-C
You can quickly test code snippets using a test case in a new project. Just create a new project and go to the Navigator in the left pane and hit the Test Navigator button. Then follow this guide
The setup code will look a little different than a swift playground, but it still allows you to prototype and play around.
There is a very good library developed by Krzysztof Zabłocki in Github entitled KZPlayground that support both code in Playgrounds for Objective-C and Swift and a lot of cool features.
I hope this can help you.
If the only purpose is to test out Objective-C snippets, i would really recommend you an OS X command line Tool project.