Dish is constantly testing things. They may not even be new channels. They could be testing new encoding systems with existing channels and comparing the results.
Yes, typically they put new channels up as a test in advance of launch. But, even then they could just be a blank slate while they wait for a fiber connection to the provider to be put in place, then they have a mile or two of cable to run in their facilities. Then they have to see how well it mixes with other channels. This of course has nothing to do with actual deal making to even launch the channel.