It has been a while, so will post a few in rapid succession to catch you up. While the rough-in plumbing has been in for a while, with the walls going in, we really needed to test it out. We also had to finish all the connections to the fresh water tank, the water pump and water heater, the shower pump, the grey water tank and the waste lines under the tiny, and lastly the exterior shower.
This video gives you a walk through of most of the plumbing components.
After making all the connections we needed to pressure test. 
A pressure gauge was attached to one of the interior outlets and since we did not have many of the fixtures yet, caps were put on the rest. We connected the water hose from the house, making sure to put a pressure regulator in line to not over do it, and turned it on. You can hear the water rushing through lines as it fills up and then it is supposed to stop. Oh oh – water was gushing from a corner. We quickly shut off to inspect. We used Pex and all connections are crimped. We must have 200 of these. The clamp was there, but I forgot to crimp an elbow – Aarrgghhh.
To make matters worse, it was located in the ceiling to the loft, so we had to take part of the floor out to repair. Well, if we had 200+ of these, one bad one was not bad. We cleaned it up and turned on the water again. No gushing water. But wait, we could hear something. It was coming from behind the bathroom wall. Crap!! Turns out a screw had penetrated the line. Since it was buried in the solid foam wall insulation, it took a while to carve it out, get enough room to make a splice, and put it back together. We found one more of these small leaks. Painful process, but so glad when it was done. The final test was to fill up all the lines, shut off the water inlet, and record the pressure on the gauge. Wait 24 hours and check again. If the same – no leaks. We passed.
We could now focus on building the bathroom with sink, shower, washer and dryer (link coming soon). We will continue testing plumbing after that is done, checking the shower pump, drainage, and the fresh water tank and pump.