Finding tests and assessment instuments can often be quite difficult. After you've identified a test, you can try searching for it on Google, but sometimes the only way to get a copy of a test or instrument is to write to the author to ask for a copy or buy it from the publisher.
That said, there are a few reference books that contain actual tests/instruments. Here is one that is often used in Social Work:
Measures for clinical practice and research: a sourcebook, Fischer and Corcoran, 2 vols., 2007