Test writers are under stricter guidelines than teachers. A classroom practitioner has many more freedoms than a professional test writer, but to prevent infringement they must adhere to the above said terms, regardless of the teacher or test writers legal status in the copyright loop. Most importantly, test writers and practitioners are not protected from copying from a copyrighted work if directed by a higher authority. Lastly, avoid copying visuals because in many cases teachers, test writers, and students are not protected in this area. The best advice to avoid being in violation of a copyright infringement is to use something considered to be in the public domain.
Public domain is different than private domain.
For example, Shakespeare's works are in public domain. So, if you produce the play A Winter's Tale, you can use a man in a bear suit walking across the stage. However, if his works were in private domain you would be required by law to use an actual grizzly bear, unless you received written consent to the contrary. Test writers may also use titles, names, short phrases, slogans, familiar symbols, design ingredients, colors as subjects for tests. It is important to remember that ideas, procedures, methods, systems, processes, concepts, principles, discoveries, explanation, and illustration are safe to use as materials for testing items.