When you are editing the course, lesson or test, you can preview the content exactly how it will looks like to the learner on the portal.
Deactivated courses, lessons and tests cannot be previewed.
Steps:
Previewing the course will enroll you to the course and create various data about course progress. To clear the data, you can reset the course anytime.
Steps to preview the test while editing:
Submitting test in preview mode create a test attempt in the same way as when the test is run by a learner. To clear the data, you can delete the test results.