Tests and measurements are typically used for research and assessment. They can be surveys, questionnaires, scales and other instruments that measure outcomes. Tests are usually only available for purchase and the full text may not be readily available.
Reviews of tests are available through the Mental Measurements Yearbook. If there isn't a review of the test you're looking for, search for the name of the test in Google Scholar or in PsycINFO to find the article it was originally published in. That article will give you all the information about the development of the test.
APA PsycTESTS, linked below, contains the full text of some tests, instruments and scales. Sometimes you can view a test because it has been published in a journal article or dissertation. In PsycTESTS, in the advanced search section, change the field to "tests & measures" in order to find tests or you can select that filter once your do the search and get your results.
You can search the Tests and Measurements field of APA PsycINFO to find articles that used a particular test or measurement. This can help you answer questions about how the measurement has been used, and whether there are related tests in a particular research interest. See below example: