We recently built a plugin for Ready! API that lets you create functional tests for MQTT by using a Publish test step in combination with a Receive test step. Ready! API is a family of API testing tools built around our open source testing tools, SoapUI. You can use it for free for 14 days and the plugin is always free of charge. Since this is our first foray into supporting IoT protocols, we’d love to get some feedback from this group. We’ve also made it open source so if anyone wants to contribute some improvements to it, please do!
We also have some ideas about next steps, including load test capabilities, "disruption" testing (i.e., unstable connections), and compliance testing. If you have any thoughts about what you'd like to see for that kind of feature set, please let me know.
You can download a copy of Ready! API here: http://smartbear.com/product/ready-api-family/free-trial/
The plugin is in the list of available plugins in the Plugin Manager on the top tool bar.
Instructions for using it are here: http://smartbear.com/smartbear-developer-network/mqtt-test-steps/
Source code is here: https://github.com/SmartBear/ready-mqtt-plugin
Thanks in advance for any feedback you have!