My client is testing the test version of the firmware I delivered for him as I write this. I'm very anxious to hear his reaction, as he will base the decision of whether to fund bringing the product to market on how his testing of this proof of concept goes.
He had some trouble with his testing at first, but I was able to help him get the tests working after talking to him on the phone for a little bit. But I had to let him go work on his own because I had written up a complicated test procedure to go with some test tools that I gave him tonight, that would prove to him that the product actually did what it was intended to. I needed to let him study my test procedure and try it out.
It would really be a problem for me if he doesn't want to continue with the development. I have other work in the pipeline, but it would be a while before I could see a paycheck from any of the other projects.