For wired decoders I used always used a test fixture of some sort in case I wanted to test it before installation or in case I had issues with it and wanted to test it separately. In the February 2011 post Building a decoder tester I showed how I built the one I am currently using.
Of course now there are many decoder models that have no wires. I wanted to come with with some sort of easy connections to my decoder tester to accommodate those. The first one I have done is for the TCS CN and CN-GP decoders as I use a lot of those.
I drilled and tapped 2-56 holes on each half of an Atlas GP7 frame half to secure 22 gauge wires. Then mounted this to a small 1/2 inch thick piece of plywood for stability. Space for the fuel tank part of the frame was routed out of the plywood and 1/4 inch thick plywood rails on each side hold the frame in place.
The 22 gauge wires from the frame and motor wires from the decoder are connected to the decoder tester. I had included banana jacks on the decoder tester with this purpose in mind but find that the wire binding post work just fine.
This setup should also work on with the TCS MT1500 decoder.