Many tests are not freely available to the public. Often they need to be purchased from a publisher. When a test is freely available, there are some sources that will direct you to the instrument.
Some articles in PsycINFO include complete testing instruments. You will need to look at the full text of articles to find out whether or not the instrument is included.
The Tests and Measures in the Social Sciences page hosted at UT Arlington provides a list of books that include complete assessment instruments. This resource works best if you already know the name of the assessment you are looking for. For instance, try a search for the "Liking People Scale." Click on the first link in the results list, and you will find that this scale is available in a book entitled Measurement of love and intimate relations (1993). A search for this title in the ND Catalog will determine that ND owns the book, and it is shelved on the 9th floor with the call number HM 132. T84 1993.
The University of South Florida's Library has also built a database for locating tests that are available in books. The database includes links to WorldCat records which can tell you whether or not Notre Dame owns the books in which the tests are published.