Finding complete instruments (tests or scales) can be challenging. Published tests (or commercial tests) cannot usually be purchased by libraries; instead test publishers sell them to researchers on an individual basis and they can be expensive. Often one must qualify as an administrator in order to use the test. Unpublished tests can be found in a variety of places including journal article and dissertations. The library collection contains a number of print compilations of full-text tests available in the public domain. (For more see Tests & Measures, UT Libraries guide.)
Psychological tests (from Wikipedia): "an instrument designed to measure unobserved constructs, also known as latent variables. Psychological tests are typically, but not necessarily, a series of tasks or problems that the respondent has to solve. Psychological tests can strongly resemble questionnaires, which are also designed to measure unobserved constructs, but differ in that psychological tests ask for a respondent's maximum performance whereas a questionnaire asks for a respondents typical performance. A useful psychological test must be both valid (i.e. there is evidence to support the specified interpretation of the test result) and reliable (i.e. internally consistent or give consistent results over time, across raters, etc.)"
Psychometrics (from the SAGE Encyclopedia of Social Science Research Methods): "deals with the measurement of individual differences between people. The instruments used for measurement can be psychological tests, questionnaires, personality inventories, and observational checklists. The measurement values quantify either the levels of psychological property or the ordering of these levels.These properties can be abilities (e.g. verbal intelligence, analytical reasoning, spacial orientation), skills (e.g. in manipulating control panels for traffic regulation, in chairing a meeting in a work situation), personality traits (e.g. introversion, friendliness, neuroticism), preferences (e.g. for consumer goods, politicians, authors), and attitudes (e.g. toward abortion, the political right wing, NATO intervention in other countries)."
PsycINFO, from the American Psychological Association, is a major index to psychological literature. Use it to find journal articles, book chapter, dissertations and other literature in the field of psychology. You can search the Test & measure field in the Advanced Search screen to look up research studies that used specific tests.

OR, enter search terms and select Test and measure - TM from the pull-down menu. When the word "appended" is added to the Test and measure - TM search, results will include articles in which the full text of the test is appended to the article.

View the detailed record of items in search results to see the tests used in the study, to find out if the test is appended in the article and, in some case, a link to the test information.

ERIC, the education database, allows searchers to narrow down a search by Document Type: Tests/questionnaires. Or, to look up the name of a specific test in the KW search box.
To see if a specific tool was used in a dissertation, search the name of it in Digital Dissertations and Theses. Or, if you don't know of a specific test, search in the topic in keyword field and then in the second line of the search type: (test OR instrument OR measure OR questionnaire OR survey OR scale) near/10 appendix. (helpful tip from University of Texas Libraries)
Guide to Sources of Information on Tests and Measurements from University of Illinois at Urbana-Champaign
Tests & Measures from UT Libraries
Tests and Measures from UC San Diego
Tests and Measures from University of Pittsburgh
Psychology:Finding Tests & Measures from Boston College
Health Literacy Tool Shed: Database of health literacy measures.
Questionnaire Instrument Compendium (QIC): Social-Personality Psychology (from Texas Tech)
TMdb: Tests and Measures in the Social Sciences: Lists tests available in compilation volumes (from UT Arlington)
APA: Finding Information About Psychological Tests: Information and background from the American Psychological Association. Includes related links to standards, statements on appropriate use and information on testing practices.
AERA Position Statement on High-Stakes Testing: from the American Educational Research Association
Association of Test Publishers: Organization representing providers of tests and assessment tools.
Standards for Educational and Psychological Testing
by
These testing standards are a product of the American Educational Research Association, the American Psychological Association (APA), and the National Council on Measurement in Education (NCME). Published collectively by the three organizations since 1966, it represents the gold standard in guidance on testing in the United States and in many other countries. In the past 15 years, important developments have occurred in the field of testing, requiring significant revision. Five areas, in particular, receive attention in the 2014 revision: Examining the accountability issues for the uses of tests in educational policy. Broadening the concept of accessibility of tests for all examinees. Representing more comprehensively the role of tests in the workplace. Taking into account the expanding role of technology in testing. Improving the structure of the book for better communication of the standards. Among the problem areas addressed in this revision are the following: The chapters on assessment, program evaluation, and public policy have been rewritten to address the uses of tests for educational accountability purposes. A new chapter on fairness in testing has been added to emphasize accessibility and fairness as fundamental issues in testing. The topics formerly addressed in several chapters are now combined into a single, comprehensive chapter, more broadly cast to support appropriate testing and valid score interpretations for all examinees. Specific concerns about fairness are threaded throughout the book. The chapter on workplace testing and credentialling has been reorganized to clarify when a standard is relevant to employment or credentialling. The impact of technology has been considered throughout the volume. To improve readability, individual standards are now organized under themes, and each chapter in the Foundations section now has an overarching standard. While teams of experts collaborated in developing and crafting this updated edition, each of the three organizations assumed responsibility for reviewing the work to ensure quality standards that are robust and applicable across educational and psychological contexts in which tests are developed, administered, and used.