The good news is there are times when photographers hire models for their own testing. Sometimes they can "test" experiments with new equipment or photographic techniques. Photographers may even want to test new models or experiment with their own artistic freedom without working for paying clients.
Depending on the photographer's experience and financial situation, models may or may not be compensated for money, but may only print for their portfolio. This type of test may be referred to as TFP (also referred to as fingerprint time, fingerprint testing) or TFCD (also referred to as "image" CD time). Many of these possibilities are available on the internet through the social networking model. There are many personal brand photographers also that can be found on social media.
Most likely, however, the model was the one paying the test photographer. Therefore, the model must ensure that they invest their money properly and wisely in their services when they have to pay. Not all test photographers are respected. So always ask zoning agencies which photographers they recommend or which you should avoid.
Some photographers may be new to models, so their pricing should be based on their experience. If you pay a photographer to give you a "commercial" look and they only look fashionable in their portfolio, that's an indicator that you need to show examples of their commercial work.
You would be wasting your money if you were in a smaller shopping area and only had a fashion or editorial look at your book. Business customers want to see a certain kind of "appearance." It can be quite blurry when you are touring. Likewise, with a commercial appearance, you need to continue working on making picture books with various commercial visions.