The word and concept of Test is used several ways in Moodle documentation.
In Moodle language the Quiz module, might be called a Test module. Moodlers may refer to a Quiz as a kind of student assessment. This definition can be shared by the word "test". Please refer to the Quiz index category page for a list of pages concerning some student assessment tools.
Developers in Moodle use the word test in a quality control ("test a feature") or logic process (test to see if the field is true). See dev:QA testing for more information about formal testing process.