"Printer Test Target" is an sRGB test image (JPEG compressed) for testing up to four variations of printer settings/profiles on a single sheet of 8.5x11 photo paper when printed at 4x5 inches. This is what I use for evaluating the performance (e.g. color accuracy and gamut) of profiles specific to my printer.
Three of the images you see in the target were put on the WWW by Fuji when they first promoted their S1 Pro camera. I figured Fuji spend a LOT of money creating the pictures and decided they would serve as pretty good reference photographs of skin color and overall excellent dynamic range (besides, I liked the pictures and the model was not difficult to look at).
If you decide to use the test target on your printer, please consider a note of caution. There is no printer I'm aware of that will duplicate all the primary transmitted colors you see on your monitor. Monitor blue is a lost cause, and the orchids are a lost cause (a soft proof will prove my point). Also, what goes around, comes around - there is no monitor I'm aware of that will duplicate all the primary reflective colors that your printer can produce.
There is another thing to be aware of. If you simply look at this picture via a browser that is not ICC-savvy, you will not see the true colors as they would be presented using an ICC-savvy viewer program or image editing program (e.g. Photoshop). Assuming you have an accurate profile for your monitor, Photoshop will apply corrections based on the monitor's primary chromaticity values and the picture will look fairly accurate (consistent with the gamut limitations associated with your monitor). So, in summary, be sure and test your printer's WYSIWYG performance while viewing this picture file on your monitor only when using an ICC-savvy program.