I have never been tested at a soapland or any other Fuzoku establishment. I'm glad for it too because my Japanese is conversational at best. Try not to overthink your visits - it will just add stress. When I visit soaplands (not often once a year), I speak as little as possible. There are two things to keep in mind about Fuzoku establishments: (1) They want to make money. (2) They do not want any trouble. People who speak too much CAN be viewed as troublesome (not always). I dont know what race or nationality you are, but I am African American and generally don't have problems getting into soaplands or pinsaros.
Rather then study for a test you may or may not encounter I have two suggestions. (1) I would advise you just to learn phrases that are most relevant to the type of experience you want. (2) Dress as nicely as you can. If you are in an expensive looking suit garnished with tie, cuff links, and perhaps a pocket square. While this may have the unintended consequence of looking wealthy, it will also make you look less like trouble and more like money.
One time a couple years ago, I dressed up just like I described and made my way to a Kinpei I think it was. I caught the attention of a slightly older woman, she approached me under the guise of wanting to practice her English. Long story short, rather then going to the soapland, I went to a love hotel.
