Most of the time you will set constraints to ensure that only valid inputs are chosen by constrained random, but you can send in bad data as well to see if it is handled correctly. What I am more concerned about is that you don't actually test anything at all, you just create a false illusion that you are.
Perhaps I have misunderstood, but isn't there a danger with what you're suggesting that you test a design to check it does what it should, but you're not checking to see that it doesn't do what it shouldn't? I can think of a couple of things that caught us out over the years where I thought - I wonder if random testing would have spotted that?
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.