Terms to know:
Reliability: The extent to which a measurement is free from error. The result for a person who has not changed also doesn’t change when retested at different intervals, by different people, or in different situations. Validity: the degree to which an instrument is measuring the thing it claims to measure. For example, does a test for student engagement actually measure that, or is it measuring something else, like extroversion or intelligence?
Many studies attach full-text of their testing instruments as an appendix to their final document. These can often be found through database searches. Do note that many measurement tools are protected by copyright. If planning to use a tool for research or practice, you may need to get copyright permission or pay for a license. Talk to me if you need help or further information.
To find tests and measurements in databases try searching for your topic AND your instrument.
Example: test anxiety AND ("oral interview" OR questionnaire)
