We many times will get requests for specific tests from the database HaPI, Health and Psychosocial Instruments. On rare occasions these are easy to find. But usually they are very difficult.
Sometimes you can find a journal article that has the test embedded in it, other times, it is only available for purchase. Google Scholar, PsychInfo will work to possibly locate the test within an article. But, when all else fails, Reference has some indexes that might work, but many times when the student finds out that we cannot locate what they need, they will go to Reference and pick out a test from some materials they have up there.