It is really amazing to watch because the pair ride the same movements almost as mirrors to each other at times.
The tests can be ridden all the way from Training level up!
If you are interested in starting your journey with Pas De Deux, USDF gives these recommendations:
It is first necessary to be familiar with the score sheet as well as the rules. Because the quality of execution is judged as a whole, the same score sheet is used for all competitive levels from Training through Grand Prix. International Pas de Deux competition is under the jurisdiction of the FEI and uses the Freestyle score sheet from the same level. The score sheet is available through the USDF. Once you have chosen the level you wish to compete and have all your information at hand, you are set to go.
For more information on exactly how you are judged you can go to USDF’s website here.